Advanced Functional Materials

Ultrahigh purity of single-walled carbon nanotubes (SWNCTs) with a carbon content of 99.5 wt% are formed by efficient growth of SWCNTs and partial oxidation of metal@C nanoparticles that is based on the in situ monitoring the role of working metal catalyst nanoparticles during chemical vapor deposition growth and CO₂ purification of SWCNTs.

A highly active electrocatalyst of MoS₂/MGF, where the MoS₂ nanoparticles are formed uniformly on mesoporous graphene foams (MGF) via a facile solvothermal approach, is reported. The MoS₂/MGF nanocomposites exhibit the high hydrogen evolution reaction activity with a low overpotential and large cathodic currents arising from MGF's high surface area, abundant mesopores, and highly conductive skeleton of graphene.

Morphological control over the bulk heterojunction (BHJ) microstructure of a small-molecule photovoltaic system is demonstrated using thermal treatment and solvent additives. Single crystal X-ray diffraction and transmission electron microscopy are utilized to investigate solid-state interactions and the BHJ morphology. Domain size and molecular order are crucial to achieving the 7.0% power conversion efficiency and over 90% internal quantum efficiency exhibited under optimized conditions.

A graphene oxide and copper-centered metal organic framework composite shows good performance as a tri-functional catalyst for the hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and oxygen reduction reaction (ORR).

H-doped black titania with a crystalline core/amorphous shell structure (TiO₂@TiO_2-xH_x) is synthesized by hydrogen plasma. Solar absorption is enhanced due to localized surface plasmon resonance. H doping reduces oxygen vacancies and eliminates the recombination of light-excited electrons and holes. These behaviors enable the black titania to be excellent for water splitting.

The incorporation of carbon nanofibers into plasticized poly(vinyl chloride) (PVC) or poly(dimethylsiloxane) (PDMS) elastomers yields conductive nanocomposites that can be printed on fabrics to produce electronic textiles (e.g., strain sensors). Upon strain cycling, the nanofibers undergo reorientation and subsequent separation, causing the nanocomposites to exhibit strain-reversible piezoresistivity.

Significant advances in surface nanoarchitecture for bio-applications such as biocompatible surfaces, antifouling systems, implantation, stem cell research, organ-on-chip, and lab-on-chip are reviewed. The design of intelligent surfaces with both space- and time-dependent functionality requires selected materials, methodology used for nanostructuring, an active cell surface interface, patterning, drug depots in the substrate, and stimuli response (including multi-trigger response of system and self-regulation).

An in situ approach to activate semiconductor nanocrystals (SNCs) mediated by self-limited nanocrystallization of the glassy phase is proposed. The protocol is highly effective for intentionally introducing various cation/anion dopants or their combinations into Ga₂O₃ SNCs. It offers the possibility of precisely manipulating the photon emission of SNCs to cover the ultraviolet, visible and even near-infrared spectral ranges by simply tuning inert co-dopants.

The continuous assembly of polymers (CAP) is utilized to fabricate advanced functional nanocoatings with tunable film compositions on various substrates. The versatility of CAP is demonstrated by the formation of (super)hydrophobic coatings on hydrophilic substrates including paper, cotton, aluminium foil, and glass. Moreover, by simple alternate dipping in hydrophilic and hydrophobic macro-crosslinker solutions, novel stratified amphiphilic films can be assembled via CAP.

The influence of intraphase microstructure on the performance of organic photovoltaics (OPVs) is studied utilizing a bilayer (planar heterojunction) device architecture. Devices in which the donor layer exhibits subtle differences in microstructure are compared, and these differences are shown to affect critical parameters (energy levels, charge transport properties) having a significant impact on performance.

A new phase boundary separating the Cc and R3c phases is revealed in (1–x)(Bi_1/2Na_1/2)TiO₃−xBaTiO₃, the most extensively studied lead-free piezoelectric. The unique electron diffraction method leading to this discovery may also be used to facilitate the analysis of oxygen octahedra tilting in other perovskite ferroelectrics.

A self-standing and flexible Li₄Ti₅O₁₂ electrode is assembled via a vacuum filtration process of Li₄Ti₅O₁₂ nanosheets with N-doped carbon coating. This flexible electrode shows an excellent rate capability and a significantly improved cycling performance.

A fabrication method is introduced that utilizes masked deposition and selective wetting to produce hyperelastic electronic circuits that are composed of a thin elastomer film embedded with microchannels of liquid-phase gallium-indium (Ga-In) alloy. This method enables geometries that cannot be produced by injection and allows for the automated, high-volume production of Ga-In-based stretchable conductors.

The Modality 2 inverse design is applied to the search for good p-type TCO from the well-documented compounds. Guided by the d⁵ design principle, 13 Mn(II) ternary oxides from the ICSD are selected and narrowed to two “best-of-class” candidates by high-throughput first-principles computational screening. In the end, Li-doped Cr₂MnO₄ is obtained, as a novel p-type TCO by design.

The origin of the photoluminescence (PL) behavior of graphene quantum dots (GQDs) is investigated. Following a series of annealing experiments designed to passivate the free edges, the PL in GQDs originates from edge-states, and an edge-passivation subsequent to synthesis quenches the PL.

Novel single-walled carbon nanotube/phase change material (SWNT/PCM) composites have UV-vis sunlight harvesting, light-thermal conversion, thermal energy storage, and form-stable effects. Upon UV-vis light irradiation, the light-to-heat conversion and thermal storage efficiency (η) of the obtained SWNT/PCM composites is over 0.84 using the photothermal calculation method.

Water soluble and chemically compatible Prussian blue nanoparticles (PBNPs) and reduced graphene oxide (RGO) are synthesized. These two kinds of stable and low-cost nanoscale materials are used as building blocks to prepare electrically enhanced and functionally endorsed hybrid nanosheets, which are further transformed into free-standing graphene paper for high-performance electrocatalysis and application as flexible sensors.

Sensor arrays for cyclohexanone and nitromethane are fabricated using single-walled carbon nanotubes (SWCNTs) that are covalently functionalized with different types of selector units. The thiourea, urea and squaramide-based selectors are optimized for improved sensing response. The sensors can be easily fabricated and integrated into electronic circuits. Furthermore, they show a very high level of reproducibility and promising long-term stability.

Using an exciplex-forming co-host, an organic light-emitting diode (OLED) with ultimate efficiency is produced. The OLED has a low turn-on voltage of 2.4 V, a very high external quantum efficiency (EQE) of 29.1%, a very high power efficiency of 124 lm W⁻¹, and an extremely low efficiency roll-off. The EQE of the optimized OLED is maintained at more than 27.8%, up to 10 000 cd m⁻².

A microscopic theory for hybrid improper ferroelectrics is reported, whereby a spontaneous polarization emerges from an antiferroelectric state owing to the combination of octahedral rotations and cation ordering. A materials design framework is constructed based on crystal-chemistry descriptors rooted in group theory— enabling the design of artificial oxides with large electric polarizations and small energetic switching barriers.

Red-emitting CdSe quantum dots coated with pyridine, self assembled into a layer over a large area single-sheet graphene, serve as photosensitizers. Pyridine coating of the quantum dots enhances their adhesion to the graphene surface, and provides electronic coupling that is essential for efficient photoinduced electron transfer from the CdSe to the 2D carbon allotrope. A hole shift to the pyridinium ligands accompanies the electron transfer, making this interfacial charge transfer electrostatically favorable.

Vascularization in complex organisms plays an important role in reducing the characteristic diffusion length scale of tissue structures with large dimensions. This strategy is recapitulated in synthetic shape-memory materials. Vascular networks accelerate phase transitions and increase recovery rates in stimuli-responsive polymers by reducing the characteristic diffusion length scale of the bulk material.

Recent progress in the photocatalysis development of graphene-based nanocomposites is highlighted and evaluated. The focus is on the mechanism of graphene-enhanced photocatalytic activity, the understanding of electron transport, and the applications of graphene-based photocatalysts for water splitting, degradation or oxidization of organic contaminants, photoreduction of CO₂ into renewable fuels, toxic elimination of heavy metal ions, and antibacterial applications.

Enhanced mobility and conductivity are reached in polycrystalline zinc oxide films by hydrogen plasma post-deposition treatment. Opto-electrical characterization methods show that electron trap defects at grain boundaries are passivated, and free electron concentration is increased, and that the electron transport is no longer limited by grain boundary scattering, even for non-intentionally doped films.

An effective and simple approach for boosting the performance of white organic light-emitting devices (WOLEDs) is demonstrated. A modified device structure consisting of a composite blue host that can significantly improve both device efficiency and efficiency roll-off is developed. With the modified structure, a WOLED exhibiting twofold enhancement in the total efficacy from 31 up to 61 lm W⁻¹ is realized.

Bone metastasis depends on the complex interactions between the primary tumor and the metastatic niche. Metastasis models can illuminate this poorly understood phenomenon. Antheraea mylitta silk fibroin scaffold based 3D in vitro co-cultured tumor model systems can help in understanding the tumor-stroma interactions during metastasis as well as evaluate chemoresistance.

A series of ultralow-bandgap polymers made by copolymerizing various electron-rich units with a newly conceived thienoisoindigo (TIIG) moiety is presented for organic field-effect transistors. Investigation of their field-effect performance indicates that the TIIG-based polymers can function as either a unipolar p-type or ambipolar semiconductor via the variation of the electrode metals, independent of the electron affinity of the counterparts.

Flexible multi-colored electrochromic (EC) and volatile polymer memory devices are fabricated from starburst triarylamine-based polyimide. The polyimide possesses static random access memory behavior and longer retention time than other C(CF₃)₂-based polyimides. The flexible EC device showed multicolor electrochromism with excellent stability for long-term EC operation. The characteristics suggest that the novel starburst triarylamine-containing polyimide has great potential for future flexible electronics.

A water-soluble mechanochromic luminescent pyrene derivative with two hydrophilic dendrons is reported. This amphiphilic dumbbell-shaped molecule forms micelles in water. Mechanical stimulation (grinding) of this pyrene derivative in the solid state results in a change of the photoluminescence from yellow to green. Subsequent exposure to water vapor induces recovery of the initial yellow photoluminescence.

Biologically inspired, kinetically controlled synthesis is used to develop a new family of nanocrystalline Pt-based catalytic electrodes. A novel carbon-carbon composite of carbon black and multiwall carbon nanotubes is formed for the control of mesoscale morphology and used as the matrix for nucleation and growth of nanocrystalline Pt, providing access to new combinations of porosity, conductivity and electrochemical hydrogen oxidation.

A new type of “smart” single-walled carbon nanotube is created by combining reversible host–guest interaction and noncovalent π–π stacking. The SWNTs hybrids not only are well dispersed in pure water, but they also exhibit switchable dispersion/aggregation states upon the alternate irradiation with UV and visible light in pure water.

Alloy scattering dominated charge transport is found in the ZrNiSn thermoelectric solid solutions. A low deformation potential and a low alloy scattering potential are derived by a quantitative modeling of electrical transport properties, which is beneficial for a relatively high mobility. These intrinsic favorable features can contribute to the high power factors of the half-Heusler alloys.

A wide compositional range of materials are proposed and applied as cathodes featuring highly competitive performance. Contrary to expectations, the formation of perovskite-brownmillerite pseudo-composites with high Ca substitution results in significant improvements to electrochemical performance and excellent thermomechanical compatibility with electrolytes. Furthermore, new insights are gained into the material surface properties controlling oxygen reduction processes.

Branched nanorods with α-Fe₂O₃ as the branches and β-MnO₂ as the stems are synthesized by the high-temperature annealing of FeOOH epitaxially grown on the β-MnO₂ nanorods. These branched nanorods present an excellent lithium-storage performance in terms of reversible capacity, cycling stability, and rate capability.

Single step production of bio-inspired hierarchical fluorinated wax crystalline surfaces, which exhibit superoleophobic characteristics, is reported. The marked surface roughness and re-entrant curvature, in combination with the low surface energy of the fluorinated wax, results in high contact angles of low-surface-tension liquids and low contact-angle hysteresis values.

Mg-based metallic glasses have good ductility and excellent cell compatibility when properly alloyed by Yb. The good bending and tensile ductility is likely due to the formation of dense shear bands and large plastic zones. The improved cell compatibility can be attributed to the good corrosion resistance and the reduced release of cations and hydrogen.

Highly elastic hydrogels containing well-defined micropatterns are engineered from recombinant human tropoelastin, the resilience-imparting protein found in all elastic human tissues. These elastic substrates are then used to engineer biomimetic cardiac tissue constructs. The micropatterned hydrogels support the alignment, intercellular communication, and synchronous beating of cardiomyocytes by providing an elastic mechanical support that mimics their dynamic mechanical properties in vivo (scale bar: 50 μm).

Wavelength-dispersive X-ray spectrometry (WDX) is applied to Bi₂Te₃ thermoelectric thin films for accurate chemical analysis. The antisite densities can thus be measured and this can be used to control the charge-carrier densities. The transport properties are compared with solutions of the linearized Boltzmann transport equation. For sputtered films, the argon concentration, which is relevant for phonon scattering, is measured.

An optically reconfigurable resistive switching diode is realized by growing ZnO nanorods on Nb-doped SrTiO₃ single crystals in solution at low temperatures. The ZnO nanorods/Nb:SrTiO₃ heterojunction forms a high-quality Schottky diode that shows persistent photoconductivity and light-controlled resistive switching behaviors with highly tunable ON and OFF memory states.

Coupling of structural and micromagnetic properties of ferromagnetic Ni-Mn-Ga shape memory thin films is investigated by means of three dimensional numerical simulations and temperature dependent magnetic force microscopy measurements across the martensite and Curie temperatures. A stress-induced magneto-crystalline anisotropy is detected within the austenite phase, which is quantified based on a model of partial flux closure.

Single layer graphene-silver nanowire network co-percolating 2D-1D hybrid transparent conducting electrodes (TCE) with very low sheet resistance-optical transparency values (22 Ω/□ (stabilized to 13 Ω/□ after 4 months) at 88% transmittance at λ = 550 nm) are achieved. The development of such a high performance (chemically/mechanically/optically stable) material is inspired by a theoretical prediction of co-percolating transport in graphene-wrapped silver nanowire network.

Straightforward preparation of various functionalized or inorganic nanowires can be achieved by a very simple method based on mixing structurally related modified amyloid peptides, which allows effective control of self-assembly. The peptides contain three-amino-acid-residue units that provide remarkable control during the entire self-assembly process, starting from a small oligomer up to the macroscopic fibril level.

A conceptual study on triple-layer PLEDs fabricated by successive solution based deposition of multiple polymer layers without extensively redissolving of existing layers is shown. Ultraviolet photoemission spectroscopy (UPS) measurements of the triple-layer assembly reveal a favorable energy level alignment at the respective material interfaces resulting in a charge carrier confinement in the emitting layer, thus enhancing maximum luminance and luminous efficiency values.

Films of poly(furfuryl glycidyl ether) (PFGE) and poly(ethylene oxide)-b-poly(furfuryl glycidyl ether) PEO-b-PFGE block copolymers are prepared and reversibly crosslinked by Diels-Alder chemistry. The self-healing of damaged surfaces is studied in detail with help of differential scanning calorimetry, depth-sensing indentation, small angle X-ray scattering and profilometry.

The impact of emissive layer architecture on the exciton recombination zone in organic light-emitting devices is investigated. A technique to measure the location and spatial extent of exciton recombination in organic light-emitting devices is demonstrated. The technique relies on the Förster energy transfer of an exciton from a luminescent guest to a dilute sensitizing molecule included in narrow strips within the emissive layer. It is found that the recombination zone depends strongly on emissive layer composition and architecture.

A novel model of collagen biomineralization is presented, based on deposition of mineral from metastable calcium and phosphate-containing solutions into demineralized sections of mouse periodontal tissues. Mineral deposits selectively into natively mineralized tissues of the tooth root with high fidelity, mimicking the pattern of mineralization in vivo, and demonstrating that the extracellular matrix of these tissues retains sufficient information to control collagen mineralization.

Average BaZrO₃ nanorod lengths are shown to increase at a significantly higher rate in YBa₂Cu₃O_7–x, compared to composite films double-doped with Y₂O₃ nanoparticles and BaZrO₃, when the growth temperature is increased. From this, the significance of interactive effects between dopants is demonstrated; this can provide additional control over nanostructured composite films.

The basic microstructure-dependent energy storage mechanisms of nanostructured MnO₂ are investigated via dynamic observation of the growth and in situ probing the mechanical properties by using in situ AFM. A series of dramatic evolutions of nanostructured MnO₂ involving progressive nucleation, three-dimensional growth, reversible expansion, proton intercalation induced softening, and self-accommodation phenomena can be correlated to its remarkable energy storage performance.

Novel functionalized three-dimensionally ordered macroporous (3DOM) polymeric materials with well-interconnected and chemically stable structures are created through templating with latex colloidal crystals. These materials display improved CO₂ air capture performance compared to a commercially available resin. A versatile strategy is developed to prepare functional porous polymers by colloidal crystal templating, which opens up the use of 3DOM materials for CO₂ capture.

An effective method for nondestructive characterization of graphene defects is shown by enhancing oxidation of a Cu film underneath graphene through the graphene grain boundaries in air by electron injection supplied from electrochemical reaction of the graphene/Cu film. This process involves no appreciable oxidation of the graphene layer or the graphene grain boundary, as confirmed by detailed Raman and X-ray photoelectron spectroscopy.

Silk hydrogels are soft biomaterials of stiffness matching that of nervous system tissues. Significant chick dorsal root ganglion explant outgrowth is exhibited on 2 to 4% w/v silk hydrogels supplemented with neurotrophic factors exemplifying their employment in extracellular matrix functionalization for neural tissue engineering applications.

Integrating Er³⁺ ions in a hybrid Mo₆-PMMA hybrid matrix enables the sensitization of its IR photoluminescence upon irradiation anywhere in the octahedral metallic cluster absorption band. Meanwhile it causes a noticeable decrease of the Mo₆ red luminescence. Mo₆ clusters being covalently linked to polymer strands, the hybrid material shows excellent aging behavior, leaving promising perspectives for telecom applications.

A thin sheet of acrylic elastomer, coated with black carbon conductive grease on both sides, is equi-biaxially stretched by applying radial forces to its circumference. In its unstretched state, the elastomer thickness is 0.5 mm, and the electroded radius is 2.0 cm corresponding to a mass of dielectric elastomer of 0.60 g.

Novel Flexible Nonvolatile Transistor Memory Devices based on the electrospun nanofiber of poly(3-hexylthiophene):surface-modified gold nanoparticles show a low voltage operation (±5 V), large threshold voltage shift (3.5–10.6 V), long retention times (>10⁴ s) and good endurance properties (>100 cycles) regardless of mechanical bending stress.

2,5-Diaryl-1,3,4-oxadiazole derivatives are shown to be versatile cyclometalating C^N and coordinating N^N ligands for ionic iridium complexes that are fabricated into light-emitting electrochemical cells (LECs). High brightness red emission from a LEC at a driving voltage of 10 V is observed.

Humidity-sensitive polypyrrole films can provide an insight to the development of an origami robot fabricated by folding the polypyrrole film. The principle lies in the electrically induced changes in the elastic modulus caused by desorption of water vapor due to Joule heating, which is responsible for amplifying a contraction of the film to more than a 100-fold expansion.

The responsiveness to external magnetic fields is a critical parameter for the successful application of nanomagnets in biomedicine as fast and complete magnetic separations are essential. Here, the superior separation performance of strongly magnetizable carbon-coated cementite nanoparticles over magnetite nanomagnets from stagnant/flowing human blood is shown. Beyond, a robust quantification approach for iron-based nanomaterials in iron-rich matrices is presented.

The different exfoliation routes of graphite to produce graphene by sonication in solvent, chemical oxidation, and electrochemical oxidation are compared. The results obtained show the trade-off between exfoliation speed and preservation of graphene quality. A key step to achieve efficient exfoliation is to couple gas production and mechanical exfoliation on a macroscale with non-covalent exfoliation and preservation of graphene properties on a molecular scale.

Spatial variability of bias-dependent electrochemical processes on a (La_0.5Sr_0.5)₂CoO_4±δ modified (La_xSr_1–x)CoO_3–δ surface is studied using first-order reversal curve method in electrochemical strain microscopy. Reversible oxygen reduction/evolution reaction (ORR/OER) is activated at voltages as low as 3–4 V. The degree of bias-induced transformation increases with applied bias. ORR/OER is shown to be activated in grains at relatively low biases and larger voltages at grain boundaries.

Polysaccharide multilayer films based on antimicrobial peptide functionalized hyaluronic acid as polyanion and chitosan as polycation, are deposited on planar surfaces with the aim of designing a self-defensive coating against both bacteria and yeasts.

A novel method for the fabrication of a uniform ultrathin multilayer film composed of alternating poly(p-phenylene vinylene) and reduced graphene oxide layers on a plastic substrate is reported for flexible optoelectronic applications. The ultrathin photodiode exhibits extraordinary optoelectric characteristics, including photocurrent and photoresponsivity; these are among the best values achieved in carbon-based materials.

A seedless solution process is developed to control the morphologies and orientation of crystalline ZnO micro/nanowires on graphene sheets by face-down floating or face-up in the solution. The UV detectors based on vertically aligned ZnO micro/nanowires on graphene show high responsivity and fast response.

Solid phase epitaxy of the amorphous alloy CoFeB is used to fabricate crystalline ferromagnet/graphite interfaces, which are of great interest for carbon spintronics but hardly achievable with conventional thin film deposition techniques. The heterointerface features a strong body-centred-cubic (110) texture and is free from boron accumulation upon crystallization, favorable for obtaining a high spin polarization at the CoFe/graphite interface.

Closed dc cloaks can render a conducting object invisible to external detection and distortions of probing currents due to the embedded object can be limited to inside the cloak. Using negative conductivities, exterior dc cloaks that make a nearby object invisible to the outside detectors can be realized.

Novel all-natural microcapsules fabricated from biopolymers, protein (gelatin) and resin (shellac), using a simple extrusion method. Furthermore, a range of biorelated applications including encapsulation and release of bioactives, loading of colorants and pH sensitive dye, temperature-triggered flavor release, and enzyme immobilization are successfully demonstrated.

A versatile approach based on nanosphere lithography is proposed to generate surface-imprinted polymers for selective protein recognition. Nanogravimetric measurements demonstrate that the protein (avidin) coating of the nanospheres generates selective recognition sites for avidin on the surface of the PEDOT/PSS film. This methodology coupled with oriented conjugation of the macromolecular template to the nanospheres offers the possibility of site-directed imprinting.

Engineering marvels found throughout living nature provide inspiration to researchers solving technical challenges. For example, the skins of fast-swimming sharks intrigue researchers because their riblet microstructures lead to low drag, self-cleaning, and antifouling properties. An overview of shark skin related studies that have been conducted in both open and closed channel flow experiments is presented. Adapted with permission.24 Copyright 2012, Royal Society of Chemistry.

A facile self-assembly method is used to integrate orange luminescent gold nanoclusters (L-AuNCs), which are cancer cell targeting agents, a hydrophobic cancer drug, and a pH-responsive amphiphilic polymer into a nanocomposite theranostic system. The nanocomposite can selectively target the affected cells and unload the cancer drug via a controlled release mechanism. The release of the drug can be continuously monitored by the luminescence of the co-delivered imaging probes (L-AuNCs).

Three-dimensional micropatterning of dual-crosslinked oxidized, methacrylated alginate (OMA)/8-arm PEG amine (PEG) hydrogels containing human adipose-derived stem cells (hASCs) is employed to regulate hASC fate. The micropatterned dual-crosslinked OMA/PEG hydrogels for hASC encapsulation yield relatively uniform cell clusters, which scale in size with micropatterned dimensions.

Materials, designs, and integration techniques are presented for a class of water-soluble electronics capable of fabrication using wafer-based processes. The active components exploit biocompatible and bioresorbable materials that are capable of dissolution in biofluids. Characterization of the electronic properties of the devices, their kinetics for dissolution, and preliminary evaluations in animal models highlight key aspects of the materials and concepts.

A high figure of merit (ZT) up to 1.33 at 373 K is achieved by incorporating a tiny number of SiC particles to a traditional Bi_0.3Sb_1.7Te₃ thermoelectric material. The existence of SiC nanoinclusions in the p-type Bi_0.3Sb_1.7Te₃ thermoelectric matrix reduces the electrical resistivity and increases the Seebeck coefficient, which leads to the remarkable ZT enhancement.

Highly bendable and efficient organic solar cells are developed using solution-processed silver nanowires. The electrode and solar cell characterizations are also presented with the devices showing high performance and flexibility.

Alkaline phosphatase (ALP) is immobilized in compact polyelectrolyte complexes (CoPECs). The materials obtained in this way retain the biocatalytic activity of the enzyme, protect it from elevated temperature, and allow its fine tuning by salt concentration and temperature. Co-immobilization of magnetic particles yields easily handleable magnetic materials.

Single-crystal organic nanowire arrays are generated by a direct printing method that enables the simultaneous synthesis, alignment, and patterning of nanowires. Repeated application of the direct printing process can be used to produce high-performance organic nanowire-integrated electronics with two- or three-dimensional complex structures.

The multifunctional organic bioelectronic interfaces composed of integrated reduced graphene oxide (rGO) and drug dexamethasone 21-phosphate disodium salt (DEX)-loaded poly(3,4-ethylenedioxythiophene) (PEDOT) microelectrode arrays are reported. They can be used to manipulate the attachment, orientation, and differentiation of human mesenchymal stem cells (hMSCs) for long-term cell culturing through electrical stimulation.

Homogeneous β-Co(OH)₂ on graphene is synthesized using a simple and effective electrostatic induced spread growth method, which ensures the facile fabrication of a binder-free and mechanically robust CoO/graphene electrode by means of a layer-by-layer stacking process. When employed as an anode in Li-ion batteries, a high rate capability and excellent cycle stability up to 5000 cycles are successfully obtained.

A novel leaf-like graphene oxide (GO) with a carbon nanotube (CNT) midrib is prepared from vapor growth carbon fiber (VGCF) using the conventional Hummers method. The CNT midrib provides a natural electron diffusion path for this leaf-like GO, and therefore, this leaf-like GO with a CNT midrib displays excellent performance when applied in energy storage devices, including Li-O₂ batteries, Li-ion batteries, and supercapacitors.

A template-free, high-throughput patterning technique—vibrational indentation-driven patterning (VIP)—realizes continuous, period-tunable fabrication of micro/nanometer-scale gratings by vertical indentations of a vibrating flat tool edge on a moving substrate. By modulating the tool vibration, substrate feeding rate, and the tool tilting angle, the period-variable chirped gratings and angle-tunable blazed gratings can be easily achieved.

Flower-like hierarchical SnO₂ nanostructures are assembled from single-crystalline SnO₂ nanosheets with high-index (11) and (10) exposed facets. Sn²⁺ self-doping leads to formation of tunable oxygen vacancy bandgap states and extended absorption in the visible spectral range. This work highlights the possibility of simultaneous engineering of surface energetics and electronic properties of SnO₂ based materials.

The chemical stability of epitaxial silicene results in a low reactivity with O₂ when dosing up to 1000 L and in a progressive oxidation under ambient conditions. Non-destructive Al- and Al₂O₃-based encapsulation approaches that can be exploited for ex situ characterization of silicene and for gated silicene devices (irrespective of the support substrate) are engineered.

Covalent bridging of the dicyanovinyl group with the adjacent thiophene ring of small push-pull molecular donors based on triarylamines leads to a significant improvement of the efficiency of the resulting organic solar cells due to the simultaneous increase of the fill factor and open-circuit voltage.

A multifunctional nanoplatform based on the Cu₉S₅@mSiO₂-PEG core-shell nanocomposites demonstrates an excellent biocompatibility and can be used for combining photothermal- and chemotherapies with infrared thermal imaging of cancer treatment.

Direct synthesis of multi-layer graphene and porous carbon woven composite films by chemical vapor deposition is reported. The composite films integrate the dual advantages of graphene and porous carbon, having not only the excellent electrical properties and flexibility of graphene but also the porous characteristics of amorphous carbon, creating a new platform for a variety of applications, such as supercapacitors.

An orange organic light emitting diode (OLED) with controlled co-doping of green and red phosphorescent dopants achieves a low turn-on voltage of 2.4 V and a very high EQE of 25.0%. The OLED demonstrates an external quantum efficiency over 21% at 10 000 cdm⁻². The orange OLED displays a very good orange color (Commission Internationaled'Eclairage of (0.501, 0.478) at 1000 cdm⁻²) with very little color shift with increasing luminance.

An effective way to synthesize efficient CO₂ adsorbents from pillared materials is developed on the basis of an electrostatically derived self-assembly between exfoliated 2D nanosheets and two kinds of guest nanoclusters. The co-pillaring of basic CdO with Cr₂O₃ makes it possible to improve the microporosity and basicity of the resulting pore structure and to enhance the CO₂ adsorption function and thermal stability of pillared materials.

The collective behaviors of multiple receptor-ligand bonds between a cell and a transversely isotropic matrix are investigated using a two-level model in which the reversible processes of stochastic bond rupture and rebinding at molecular scale and the elastic response of transversely isotropic materials to bond force distributions at continuum scale are integrated.

Unique near-field enhanced plasmonic-magnetic bifunctional nanotubes are fabricated and their plasmonic properties are investigated by both experimentation and theoretical modeling. By leveraging the bifunctionality, a nanotube can be precisely transported to a single living Chinese hamster ovary (CHO) cell amidst many and its membrane chemistry (lipid and protein) is revealed with surface-enhanced Raman scattering (SERS) spectroscopy.

Bio-inspired synthesis techniques are capable of producing bio-inorganic composite materials under benign reaction conditions. A facile method for the antimicrobial functionalization of such composites is described. The nitrogen moieties associated with the biopolymers entrapped within the hybrid material are chlorinated in situ to yield halamine compounds. These halamine-charged materials exhibit potent bactericidal and sporicidal activity.

Niobium nanowires are twisted to form strong (0.4 to 1.1 GPa) and highly conductive (3 × 10⁶ S m⁻¹) yarns. Impregnation with paraffin wax produces linear and large torsional actuation in response to heating and cooling.

A series of iron oxide/reduced graphene oxide composites are synthesized in one-step by a simple microwave-assisted non-aqueous sol-gel route in just few minutes. The precise characterization and comparison between the sample studied allow elucidation of structure–property relationships and the improvement of electrochemical performance targeting Li-Ion battery applications.

A carbon nanotube phase-change nanocomposite with a hydrogel achieves giant temperature coefficients of resistance resulting from a phase-transition that directly changes the tunneling potential that electrons experience in moving between nearby nanotubes. The bolometric photoresponses of this material are studied and its giant responses to temperature and humidity give it great potential for sensor applications and uncooled infrared detection.

A very simple, room-temperature nanosoldering of a Ag nanowire percolation network by conducting-polymer-assisted nanowire joining is developed to demonstrate highly flexible, and even stretchable, transparent conductors. Furthermore, a large area (A4-size) transparent conductor and a flexible touch panel on a non-flat surface are fabricated to demonstrate the possibility of cost-effective mass production and the applicability to the unconventional arbitrary soft, non-flat surfaces.

A new ionic current rectification device responsive to a broad range of pH stimuli is established using highly ordered nanochannels of porous anodic alumina membrane with abrupt surface charge discontinuity. Due to the protonation/deprotonation of the patterned amine and the remaining intrinsic hydroxyl groups, the nanochannel-array-based device is able to regulate ion transport selectivity and has ionic current rectification properties.

The first systematic study of the impact of shaping on the beneficial effects of intracrystalline mesopores on mass transfer in hierarchical ZSM-5 is presented. Using gravimetric adsorption studies of a bulky alkane probe, the enhancing effect of the developed mesopores can be preserved in multicomponent millimeter-sized granules and extrudates.

In the quest for alternative two-dimensional semiconductors, layered molybdenum trioxide and dichalcogenides are gaining significant scientific interest. This Feature Article delivers a comprehensive review of the fundamental properties, synthesis techniques, and applications of layered MoO₃, MoS₂, MoSe₂, and MoTe₂ as well as exploring their future prospects in the field of two-dimensional semiconductors.

Ferroelectric polarization switching is sensitively affected by phenomena on multiple length scales, giving rise to complex voltage- and time-controlled behavior. Spatially resolved switching dynamics in ferroelectric nanocapacitors are explored as a function of voltage pulse time and magnitude. A remarkable persistence of formal macroscopic scaling laws for polarization switching based on classical models down to nanoscale volumes is observed.

The measured bimolecular recombination rate of electrons and holes in a polymer:fullerene blend is 20 times smaller than the Langevin rate. The reduced rate is explained in terms of dissociation of electron-hole encounter complexes into free charge carriers rather than decay to the ground state.

White light scattering cells in the flexible skin of cuttlefish (Sepia officinalis) are described. How the structure and composition of leucophores serve as passive reflectors approximating optical properties of a broadband Lambertian surface is investigated. The cuttlefish system may provide a template for bio-inspired approaches to efficient light scattering in materials science and optical engineering.

White polymer light-emitting diodes with an attractive power efficiency-color rendering index (CRI)-color stability trade-off are successfully realized by blending red-green-blue (RGB) light-emitting polymers based on 9,9-bis(4-(2-ethyl-hexyloxy)phenyl)fluorene copolymerized with dibenzothiophene-S,S-dioxide (PPF-SO, blue), and benzothiadiazole (PPF-SO-BT, green) or dithienylbenzothiadiazole (PPF-SO-DHTBT, red) units.

Multifunctional nanocarriers based on up-conversion luminescent nanoparticles of NaYF₄:Yb³⁺/Er³⁺ core (UCNPs) and thermo/pH-coupling sensitive polymer poly[(N-isopropylacrylamide)-co-(methacrylic acid)] brushes gated mesoporous silica shell are reported. They have applications in cancer theranostics, including fluorescence imaging, and for controlled drug release for therapy.

High-efficiency phosphorescent organic light-emitting diodes (OLEDs) doped with Ir(ppy)₂(acac) in an exciplex forming co-host have a preferred horizontal emitter orientation. Based on optical analysis a maximum efficiency of the OLEDs of about 30% is calculated, which matches very well with the experimental data. Furthermore, a simple method to predict the maximum efficiency achievable with a certain emitting dye in a host matrix is suggested.

Combining block copolymers with nanoparticles that are highly incompatible with one block and only slightly incompatible with the other leads to hierarchical nanoparticle structures. While the block copolymer domains evolve, the nanoparticles segregate to the least incompatible domain. Then, they phase separate from it, forming hexagonally packed arrays within its confines, where interparticle distance is determined by the ligand length.

Meso/macroscopic, honeycomb-like organized TiO₂ photoanodes with dual pores, high porosity, good interconnectivity, and excellent light scattering properties result in high efficiency solid-state dye-sensitized solar cells (7.4% at 100 mW/cm²). This value is one of the highest observed for N719 dye.

Plasmonic-induced carrier extraction enhancements (plasmonic-electrical effects) in organic solar cells (OSCs) are investigated. Using a nanoparticle (NP)-TiO₂ composite, an enhanced efficiency of 8.74% is reached. The device can efficiently operate at plasmonic wavelengths far longer than the original UV region. The enhancement is attributed to the plasmonic-induced charge injection process. This mechanism favors trap filling in TiO₂, which facilitates carrier transport in OSCs.

Fabrication of surface-confined heterometallic molecular dyads (SURHMDs) composed of optically rich and redox-active molecular building blocks yields enlargement of optical window in the visible region along with occurrence of multiple redox states at low potential. The copper-mediated intramolecular electronic communication between distinct metal centers can provide potential alternatives to the prototype semiconductor-based memory devices, information processing units, or smart photonic materials.

Strontium is used as a probe to investigate the structural transformation of amorphous calcium carbonate in sea urchin larval spicules. Sr K-edge X-ray absorption spectroscopy reveals that crystallization occurs in three stages: 1) hydrated amorphous calcium carbonate, 2) disordered calcite, and 3) mature calcite.

Using a potential-controlled dealloying approach, a core-shell nanoporous Pt-Cu bimetallic catalyst with a widely tunable Pt/Cu ratio is fabricated. The nanoporous Pt-Cu catalyst consists of a Pt-Cu alloy core and a pure Pt skin, showing high catalytic activities toward the oxygen reduction reaction and formic electro-oxidation.

A simple yet effective method is developed for the synthesis of hollow mesoporous TiO₂ nanoshells with well-controlled crystallinity and phase. It is now convenient to optimize their structures for enhanced performance in photocatalysis.

Light emission from ambipolar organic field-effect transistors is observed when they are operated in the unipolar regime. This counterintuitive unipolar light emission is quantitatively explained by injection of minority carriers into deep tail states of the semiconductor. The density of the injected minority carriers is small; they are relatively immobile and recombine close the contact with accumulated majority carriers.

The use of non-ferroelectric gate dielectrics to fabricate organic field-effect transistor memory elements by manipulating the molecular dipoles in the dielectric layer is highlighted. The applied gate bias partially aligns the orientations of the hydroxyl groups perpendicular to the substrate at the pentacene/dielectrics interface, which trap charges and cause the hysteresis.

Graphene quantum dots (GQDs)-based micro-supercapacitors are prepared using a simple eletrodeposition approach and their electrochemical properties in aqueous and ionic liquid electrolytes are studied. The GQDs-based micro-supercapacitors exhibit superior rate capability, high power response capability, and excellent cyclic stability

Flexible porous films derived from electrospun carbon nanofibers incorporated with Co₃O₄ hollow nanoparticles are efficiently fabricated and directly applied as advanced self-supported hybrid film electrodes. The exhibit very high specific capacitance and excellent electrochemical stability at high current densities.

The development of new O-BODIPYs, synthesized via the replacement of fluorine atoms by carboxylate groups in commercial (4,4-difluoro-4-bora-3a,4a-diaza-s-indacene) (F-BODIPYs), is a successful strategy to obtain optimized laser dyes. Poly(methyl methacrylate) (PMMA) doped with these new derivatives leads to laser materials that are economically affordable and have optimized emission properties in the visible spectral region.

A double-layer double wavelength antireflective (AR) coating that has 100% transmittance at both 1064 nm and 532 nm is designed with the assistance of a computer. This coating consists of top and bottom layers with refractive indices of 1.14 and 1.30. A template-free sol-gel method for the preparation of the superhydrophobic silica thin film with an ultralow refractive index is proposed.

Three nanomaterials-based fluorescent biosensors are used for DNA detection in homogeneous solution. The quenching efficiency, kinetics, differentiation ability, and influencing factors are studied, and graphene oxide (GO) exhibits the best performance, characterized by superior quenching abilities, limit of detection, and the highest discrimination for single-base mismatches

Naphthalenetetracarboxylic diimide derivatives (octyl “8” NTCDI, dimethylaminopropyl “DMP” NTCDI) and copper phthalocyanine (CuPc) are used to form a diverse organic field-effect transistor sensor array. The three-response patterns obtained from representative polar, nonpolar, acidic, and basic vapors are all different, showing the potential for this approach in rapid, low-cost electronic detection of volatile compounds.

The development of (K,Na)NbO₃-based lead-free piezoceramics is attracting great interest because of growing environmental concerns. A material concept that yields an average piezoelectric coefficient, d₃₃, of about 300 pC/N and a high level of unipolar strain up to 0.16% is reported. Most intriguingly, field-induced strain varies less than 10% from room temperature to 175 °C.

Two new techniques to create chemical and structural heterogeneities within soft alginate substrates are presented and employed to engineer anisotropic cardiac and vascular smooth muscle monolayers. These micropatterned hydrogel substrates are ideally suited for building in vitro models of muscle contractility and tissue engineering applications as they recapitulate the mechanical properties of muscle microenvironment and their anisotropic structure.

Synthesis by chemical vapor deposition of nitrogen-doped graphitic nanoribbons (N_x-GNRs) is reported using pyrazine as a N precursor. Morphological, physico-chemical, and electrical characterization of nitrogen-doped graphitic nanoribbons reveal unique characteristics associated with doping sites, such as increased reactivity and changes in the electrical response towards semiconducting-like features. These results are confirmed using first-principle theoretical studies of N-doped graphene nanoribbons.

ZnO thin films are optimized by co-doping of non-metallic dopants for high optical and electrical performance. The ZnO-based organic photovoltaic (OPV) cells and organic light-emitting diodes (OLEDs) show highly improved efficiencies compared to indium tin oxide (ITO)-based devices. The optimized ZnO films are very promising electrodes for highly efficient and cost-effective OPV cells and OLEDs.

A new type of water-soluble conjugated polymer composed of poly[(3,4-dibromo-2,5-thienylene vinylene)-co-(p-phenylene-vinylene)] (PBTPV) is synthesized. Its excellent film-forming properties, stability, and photoelectric response show good potential for organic field-effect transistor and aqueous-processable hybrid solar cell applications. The carrier mobility of the aqueous PBTPV is about 5 × 10⁻⁴ cm² V⁻¹ s⁻¹ and the power conversion efficiency of the water-processed PBTPV/CdTe nanocrystal hybrid photovoltaic devices reaches 3.3%.

Tensile strain-resistivity response of poly(3,4-ethylenedioxythiophene):poly (styrenesulfonate) (PEDOT:PSS) films is investigated according to doping with dimethylsulfoxide (DMSO) up to 60% strain without crack generation. The resistivity can be modulated under strain from invariant values to decreasing values up to 80%. The growth of conductive PEDOT-rich cores is the primary mechanism for the decrease in resistivity induced by applied strain.

Iron particles are hosted in porous alumina via a facile impregnation-reduction process. When the iron content exceeds the percolation threshold, iron networks are formed. The iron content and reduction temperature can easily tune the amplitude and frequency range of the negative permittivity and permeability. The impregnation-reduction process has great potential for the preparation of random composites with tunable double negative properties.

Mixed-matrix membranes composed of the flexible NH₂-MIL-53(Al) metal-organic framework (MOF) embedded in polyimide represent a promising alternative for CO₂ removal from natural gas and biogas. Quantitative focused ion beam scanning electron microscopy (FIB-SEM) tomography evidences an excellent filler-polymer contact. The loading of MOF crystals and its framework configuration, which can be adjusted during membrane casting, are key parameters for the gas separation performance.

An ordered mesoporous tungsten-oxide/carbon (m-WO_3−x-C-s) nanocomposite is synthesized using a block-copolymer-assisted one-pot self-assembly method. As a pseudocapacitor electrode, m-WO_3−x-C-s exhibits a high average volumetric capacitance of 340 F cm⁻³ and a gravimetric capacitance of 103 F g⁻¹. The amorphous carbon in the m-WO_3−x-C-s decreases the internal resistance of m-WO_3−x-C-s electrode by facilitating electric conduction.

High quality mesoporous metal titanate thin films are synthesized using a molten-phase-assisted self-assembly (MASA) method. The metal salts are used as a non-volatile solvent in the new assembly process. The films are converted into mesoporous titania-metal chalcogenides (TiO₂-CdS, TiO₂-CdSe, and TiO₂-ZnSe) under H₂S or H₂Se at room temperature and may find applications in solar cells, catalysis, photocatalysis, electronics, and optoelectronics.

The magnetic shape memory alloy, Ni-Mn-Ga, is shown to exhibit multi-bit non-volatile memory behavior. Using nanoindentation, local modifications of the magnetic stray field enable the patterning of magnetic information. Four magnetic-based memory states are demonstrated due to magnetic field or stress-induced twin rearrangement along two crystal orientations, each with two possible magnetic orientations.

The thin film molecular packing motifs of several new benzo[d,d]thieno[3,2-b;4,5-b]dithiophene (BTDT) derivatives have different molecular packings from their bulk crystals. Co-existence of strained lattices with their single crystal forms is speculated to have a significant effect on organic thin-film transistor (OTFT) performance.

Near-infrared-sensitive surface-enhanced Raman scattering nanoprobes (NIR SERS dots) are fabricated by forming plasmonic Au/Ag hollow-shells, which assemble on silica nanospheres. A single NIR SERS dot is capable of generating a strong SERS signal (average SERS enhancement factor value 2.8 × 10⁵) with high reproducibility. In addition, the signals from NIR SERS dots are effectively detected from deep tissues of up to 8 mm depth and have exhibited a capability for in vivo multiplex detection in a live animal study.

Nematic liquid crystals confined inside cubic scaffolds made by two-photon polymerization exhibit bistability and large memory effects in response to electric fields, due to topological defects interacting with the solid structure. When viewed through crossed polarizers, the pixels, which are initially bright, remain dark after the application of strong electric fields.

A functional “ghost” illusion device that uses inhomogeneous and anisotropic materials and is capable of creating multiple virtual images off the original object's position under the illumination of electromagnetic waves is presented. The scattering signature of the object is thus perceived as multiple targets with different geometries and compositions.

Patterned photoswitchable surfaces are prepared by employing a nitrile imine-mediated tetrazole ene cycloaddition (NITEC) photoinduced process in the presence of dipolarophiles based on photoresponsive azobenzene moieties. Trans-to-cis azobenzene isomerization of the surface allows for the spatially resolved tuning of the surface properties.

The cuticular photonic polycrystals formed by the beetle Entimus imperialis are a perfect example of a natural diamond-type triply periodic bicontinuous cubic structure with structural parameters that are optimized to open up the largest possible photonic stop gaps. Depending on whether the cuticular network is complemented by air or SiO₂, the optical properties of individual domains vary from bright coloration to no coloration and transparency.

A series of degradable, pH-sensitive, membrane-destabilizing, star-shaped polymers is synthesized. Star polymers are engineered to “sense” the drop in endosomal pH, which triggers the hydrolysis of acid-labile hydrazone linkages and release of membrane-active grafts that rupture the endosomal membrane and release the loaded siRNA cargo into the cytoplasm to produce the desired knockdown of targeted gene expression at both the mRNA and protein levels.

Metal-insulator-semiconductor (MIS) light- emitting diodes (LEDs) consisting of a graphene electrode on p-GaN substrate separated by an insulating SiO₂ layer are reported. The novel MIS-LEDs have a unique tunability of the electroluminescence (EL) spectra depending on the bias conditions. The underlying mechanism can be interpreted as the tunneling of electrons and holes through the insulating layer in both polarities, which is different from the standard p-n junction model.

PbS nanocrystal/C₆₀ fullerite photodetectors exhibiting broadband UV-vis-near IR response with high detectivity are demonstrated using a simple one-step deposition process. The devices operate without the need of a transparent conducting substrate under ambient air conditions exhibiting a fast photocurrent rise time and a biexponential microsecond decay. These devices offer an attractive low-cost solution for large-area broadband photodetectors.

The preparation of brominated tetraazaperopyrenes, their crystal structures, and their electrochemical properties are reported. These N-heterocyclic peropyrene derivatives are well-suited materials for the preparation of n-channel conducting organic thin-film transistors either by vacuum deposition or by solution processing. Additionally, the fabrication of a complementary ring oscillator on a flexible substrate is described.

Coulovoltammetric responses from films of conducting polymers coating metal electrodes allow a graphical separation, identification, and quantification of reversible and irreversible reactions; structural (shrinking, compaction, relaxation and swelling) components of the reversible film reaction; their potential domains; charges; and energies consumed by every structural process.

Molecular interaction mechanisms between silk fibroin and recombinant human tropoelastin are utilized to generate multifunctional protein alloys with different net charges. The combination of their properties in alloy format extends the versatility of both structural proteins, providing a new biocompatible, biodegradable, and charge-tunable biomaterial platform for neural repair.

Efficient random lasing (RL) from self-assembled dye-doped latex nanoparticles presenting size polydispersity is reported. Both the nanoparticle size and size polydispersity influence the RL emission properties. The use of binary mixtures of nanoparticles with different sizes improves the RL emission properties with respect to the mixture constituents separately due to an increase in the filling fraction.

Direct photopatterning of a conjugated electroactive dioxythiophene-based polymer is presented. Thin films of the polymer are spray-cast from organic solvents, followed by insolubilization via photocrosslinking. The crosslinking process does not cause any detriment to the electroactivity or optical properties of the polymer, which can be redox switched between a colored and bleached state, as desired for electrochromic displays and windows.

The defect structure of 4% La-doped BaTiO3 with 4 LaBa and a Ti vacancy is shown. The loss of Ti encourages the creation of an oxygen vacancy and the subsequent electron compensation creates Ti3+, which generates the semiconducting behavior seen for the these samples.

Magnetic silicone tubes with 67 wt% magnetic particles and an inner diameter of elliptical shape allow very efficient contractions of the tube by applying an external magnetic field. The combination of magnetic silicone tubes and a magnetic field generating device results in a magnetic peristaltic pump.

A strong dry adhesive based on interlocking of buckled shape-memory polymer (SMP) pillars is designed and investigated. The strong adhesion originates from pillar interweaving and indenting with each other, as well as the elastic energy stored in the deformed SMP pillars at room temperature. The adhesion strength and anisotropy can be tuned using the detachment temperature and pillar spacing.

Nanocontainer-based anticorrosive coatings are formed by dispersing inhibitor-loaded mesoporous silica particles throughout an epoxy primer. They offer self-healing functionality and outperform the unmodified primer. Such coatings demonstrate worse passive and active protection. Coatings containing smaller nanocontainers offer enhanced self-healing performance due to homogeneous distribution and preservation of the coating integrity.

Cathodoluminescence (CL) modulation of ZnS nanostructures by controlled morphologies, Fe/Mn doping, and measurement temperature is demonstrated. A comprehensive investigation of CL of ZnS nanostructures reveals a sharp UV band-gap emission at room temperature. The ZnS nanostructures show potential applications in luminescent materials as well as short-wavelength nanolaser light sources.

Highly stable top-gated organic nano-floating-gate memory (NFGM) devices with quasi-permanent retention characteristics are fabricated using an n-type conjugated polymer. The best polymer NFGM devices show excellent memory-related characteristics along with a wide memory window, a high on-off current ratio, and a long retention time.

Polymer-based magnetoelectric materials have great potential for advanced applications such as four-state memories, energy harvesting materials and magnetic sensors. New flexible, low cost, and easily processeble magnetoelectric materials are being developed by combining electroactive polymers and magnetostrictive materials, allowing the achievement of larger areas or non-planar structures and meeting the current technological challenges.

Multi variant surface mounted metal–organic frameworks (SURMOFs) are fabricated by sequential and stepwise growth of different MOF sub-layers on a functionalized substrate. Varied pore structures and environments in the hybrid SURMOF result in multiplex adsorption kinetics of guest molecules and thus reveal the excellent potential for advanced separation tasks.

The absorption maximum of a cis-configured squaraine dye (HSQ1) is red-shifted to 686 nm using a simple molecular design strategy. Dye-sensitized solar cells (DSCs) co-sensitized with HSQ1 and N3 (a Ru bipyridyl complex) show an energy-conversion efficiency of 8.14%. HSQ1 is the first squaraine dye to possess such a broad incident photon-to-current conversion efficiency (IPCE) response spectrum and high conversion efficiency at long wavelengths.

A simple and effective way to develop hybrid phototransistor with extraordinary optoelectronic properties is achieved by decorating semiconducting quantum dots (QDs) on a single-walled carbon nanotube (SWCNT) surface. This hybrid structure demonstrates clear negative photoresponse and optical switching behavior, which could be further tuned by applying external gate bias in the future. Moreover, this hybrid structure also demonstrates an enhancement in the optical Stark effect without applying any external electric field.

The fabrication strategy and underlying mechanisms of a highly photoisomerizable sol–gel material is investigated. Glycidoxypropyl groups and thermal annealing decisively improve the material properties for better dye photoresponse. Molecular photo-orientation promotes cooperative alignment of microscopic domains, enhancing the material response and explaining intriguing features of photoisomerization gratings, such as their potential nonlocal nature. Holographic performance is selectively exploited for either long-term or dynamic holography.

The lack of a reliable large-scale production method inhibits practical applications of MoS₂ nanosheets. To address this, a facile, efficient, and scalable method for the fabrication of high-concentration aqueous dispersion of MoS₂ nanosheets using combined grinding and sonication is developed. The exfoliation process establishes a new paradigm in the top-down fabrication of 2D nanosheets in aqueous solution.

White light reflective interferometric spectroscopy and fluorescence measurements are used to implement a novel dual-mode optical porous silicon biosensor. Quantum dots act as signal amplifiers resulting in over an order of magnitude increase in sensor response and providing a secondary means of biomolecule-specific recognition through their distinct fluorescence spectra.

Synthetic β-sheet folding antimicrobial peptides (AMPs) based upon simple recurring amphiphilic sequences of (X₁Y₁X₂Y₂)_n are designed to enhance their clinical applicability. The peptide length, types of cationic, and hydrophobic residues are systematically varied to identify broad spectrum AMPs with excellent selectivities for microbial membranes. Additionally, the strong antibiofilm and endotoxin neutralization activities of optimized β-sheet forming peptide sequences are demonstrated.

Ultrathin graphene nanofiltration membranes (uGNMs) are fabricated on microporous substrates. These graphene membranes (no more than 53-nm thick) are thin enough to have excellent flexibility and can be bent without any breakage. The uGNMs show high pure water flux and high retention for organic dyes. The dark red Direct Red 81 solution turns into colorless after filtration.

It is demonstrated that atomistic defects/grain boundaries in monolayer-graphene, grown via chemical vapor deposition, can act as diffusion pathways. Transport through these pathways can be substantially reduced by either independently growing separate membranes of graphene and then stacking them together to decrease the line-of-sight pathways or increasing the internucleation distance/grain-size of the graphene monolayer to reduce the grain boundary density.

A new porous coordination polymer, ([La(BTB)H₂O]·solvent (1⊃guest)), exhibits high CH₄ separation capability toward CO₂ and C2 hydrocarbons at room temperature. In particular, it shows good water and chemical stability and is stable at pH = 14 at 100 °C.

Transparent organic light-emitting diodes (OLEDs) with conductive, transparent poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) electrodes are carefully optimized by tuning the device structure. The efficiency of PEDOT:PSS-based OLEDs is comparable to that of conventional indium tin oxide-based OLEDs. Long-term stability of OLEDs with PEDOT:PSS is significantly improved, showing a promising future for practical applications.

Simple molecular engineering of triazine precursors enables simultaneous optimization of the texture and photoelectric properties of graphitic carbon nitride (g-CN). Thermolysis of flower-like supramolecular aggregates of melamine and cyanuric acid yields the formation of mesoporous g-CN hollow spheres with the typical nanosheet-type structure preserved in the microspheres. Such structures are highly active in the photocatalytic degradation of organic pollutants.

A combination of fluorescence and scanning Kelvin probe microscopy is used to gain insight into the operational mechanism of planar ionic transition metal complex-based light-emitting electrochemical cells. Quenching of the photoluminescence in the interelectrode gap in accord with a sharp potential drop far away from the electrodes confirm an electrochemical doping mechanism, which results in the formation of a light-emitting p-i-n junction.

The effect of laser fluence on the crystalline nature of Ge₂Sb₂Te₅ films is studied in detail. Large structural differences between the laser-irradiated and thermally annealed films are revealed to be caused by the high heating rate and short duration of the laser pulse.

Charge transport and voltage-dependent recombination losses are studied in two diketopyrrolopyrrole (DPP)-based solution-processed small molecule bulk heterojunction solar cells. Light intensity and impedance spectroscopy measurements probe the influence of nongeminate recombination losses in both systems. Further analysis suggests the increase in fill factor observed in the bis-DPP system is a direct result of the higher hole mobility.

A photoassisted and inkjet-printed covalent polymer grafting method based on the photoreduction of aryldiazonium is presented. This powerful and versatile method to obtain local surface functionalization is combined with the ligand induced electroless plating process to obtain metal patterns onto flexible and transparent substrates with excellent mechanical and electrical properties, which may find applications in flexible electronics devices.

A mesh patterned n-type single-crystalline silicon nanomembrane is complementally combined with a p-type pentacene layer to form a heterogeneous p-n junction on a flexible plastic substrate. The flexible heterogeneous photodetector also exhibits good photosensitivity and external quantum efficiency at visible wavelengths. Over 60% average transmittance in the visible spectrum is measured and outstanding mechanical bending characteristics are observed.

Superhydrophobic, porous, 3D materials composed of poly(ϵ-caprolactone) (PCL) and poly(glycerol monostearate-co-ϵ-caprolactone) (PGC-C18) as a hydrophobic dopant are fabricated using the electrospinning technique. These materials are distinct from 2D superhydrophobic surfaces with maintenance of air at the surface and within the bulk of the material, and, thus, these functional materials can be considered for new applications where time and rate of wetting dictate performance.

A hierarchical nickel compound (HNC) film is prepared using a facile, one-step, and binder-free method. The HNC demonstrates both large capacitance and superior rate capability. The capacitance reduction is only 24%, even when the scan rate is increased by 50 times. The HNC also exhibits an excellent cycle life.

A self-supporting graphene hydrogel film prepared by a simple vacuum filtration technology is used as a unique experimental platform to study how graphene interacts with biological tissues both in vitro and in vivo. This graphene-based bulk material appears to be highly biocompatible, biodegradable, and osteoinductive, demonstrating graphene's potential for bone regenerative medicine.

An ultralong siRNA gene silencing effect is achieved in cells and in animal using a functionalized siRNA nanoparticle that consists of multiple siRNA and degradable polypeptide layers. Due to the slow degradation through the layers, the particles continuously release siRNA and the in vivo gene silencing effect is consistent for more than 3 weeks with only a single treatment.

A high molar absorption coefficient dithienopyrrole dye featuring the 3D giant bis(octyloxy)biphenyl segment is synthesized and employed to fabricate a 9.3% dye-sensitized solar cell at the AM1.5G conditions. The solar cell exhibits a reduced interfacial charge recombination of photoinjected electrons with both tris(1,10-phenanthroline)cobalt(III) ions and dye cations, in comparison with its congener possessing the hexyl substitutent.

Density functional theory (DFT) is used to explore the way how alkylphosphonic acid molecules can in just one chemical step be grafted on H-terminated Si(111). It is further demonstrated by means of in situ infrared spectroscopy and DFT calculations that the weak link of an alkylphosphonic acid is the P-C bond, with typical release of the carbon ligand around 500 °C. Finally, after release of the carbon ligand, an unsaturated electron configuration is driving force for the phosphorous to start the monolayer doping process.

Hierarchical MgFe-layered double hydroxide (LDH) microspheres with tunable interior structure (hollow, yolk−shell, and solid) are synthesized by a facile and cost-effective surfactant-templated method. The resulting hollow LDH microspheres yields largely enhanced activity as well as robust durability towards ethanol electro-oxidation, owing to the significantly improved mass transport and faradaic redox reaction.

A new dicyanovinyl-substituted diketopyrrolopyrrole (DPP)-based small molecule, DPP-T-DCV, shows outstanding electron mobility (μ_e) in solution-processed single-crystal OFETs (SC-OFETs). The molecular structure of DPP-T-DCV, SC-OFETs device structure, and atomic force microscopy images of the film surface of the DPP-T-DCV crystal device are shown. SC-OFETs exhibit μ_e as high as 0.96 cm² V⁻¹ s⁻¹ with on/off current ratio of ≈10⁵.

A graphene-based mesoporous SnO₂ composite is prepared via in situ growth of mesoporous SnO₂ on the graphene surface using cetyltrimethylammonium bromide (CTAB) as a template. Because of the high specific surface area and stable mesostructure of SnO₂ nanocrystalline on graphene, it displays higher reversible capacity, better cycle performance, and better rate capability compared to mesoporous SnO₂ and graphene-based non-porous SnO₂.

Thermal polymerization of a conjugated polymer is performed directly on the device electrode using solution-processable monomers. The resulting immobilized polymer is electroactive and it is reversibly switched electrotrochemically between its colored states. The polymer is successfully used as the electrochromic layer in a working device with repeated color switching.

Metallodielectric materials with plasmonic resonances at optical and infrared wavelengths are attracting increasing interest, due to their potential novel applications in photonics, plasmonics and photovoltaics. Here, a manufacturing method is presented with experimental realizations of volumetric nanocomposites doped with plasmonic nanoparticles that exhibit resonances at visible/infrared wavelengths.

Narrow ranges of morphological properties are typically required to achieve high performance in bulk heterojunction organic solar cells. This is not the case for the particular fluorinated polymer-based blend investigated, for which excellent performance is achieved for a range of domain sizes and domain purities. Broad processing latitudes and unconventionally thick active layers afforded by this material offer the potential to rapidly fabricate high performing devices without strict morphological control.

A silk scaffold is patterned with porous microchannels for engineering vascularized tissues. Microchannel dimensions range from 25 to 300 μm and endothelial cells proliferate to confluence within the channels. The microchannels are enclosed with biocompatible tissue adhesive. The scaffold supports endothelial lumen formation in the enclosed micochannels and supports stem cell co-culture in the bulk space.

A system for controlled release of small molecular corrosion inhibitors and antifouling agents is designed to entrap the active compounds and open the nanovalves only in the presence of pH lowering and sulfide ions, obtaining a multifunctional coating with self-healing anticorrosion and antifouling properties.

Fluorescent silica nanoparticles (FSNs) are prepared by incorporating dye into a mesoporous silica nanoparticle synthesis procedure. The particles do not leach dye and have strong, stable fluorescence. FSNs functionalized with antibody specific for Neisseria gonorrhoeae selectively bind Neisseria gonorrhoeae in flow cytometry experiments.

Rigidity photopatterns are created by the photo-crosslinking of a polyelectrolyte multilayer film made of a photoreactive hyaluronan derivative. Orientation of C2C12 myoblasts and nuclear elongation is observed on linear micropatterns.

Electrospun nonwovens with chameleon-type surface properties are obtained by green electrospinning of acrylate dispersions with ionic moieties followed by photo cross-linking. The resulting chameleon nonwovens can be coated by layer-by-layer deposition with a large variety of different functional materials including dyes, antibacterial compounds, silver, and gold nanoparticles.

Al-polypropylene nanocomposites are promising pulse-power capacitor materials, with resistivities of ≈ 10¹²–10¹⁵ Ω·cm, low dielectric loss in the 100 Hz–1 MHz frequency range, and recoverable energy storage as high as 14.4 J/cm³. These conductive-insulator composites obey the percolation law for two-phase composites, reaching maximum permittivity values, ϵ_r, as high as 15.4 before the percolation threshold volume fraction, v_f = 0.16.

The interplay between surface tension, viscosity, and drying time of organic semiconducting inks is taken into account to fabricate homogeneous active layers for organic light-emitting diodes (OLEDs) by gravure printing. The optimal formulation of the ink is identified when its properties allow a film leveling time shorter that the critical “freezing” time.

Laser induced hydrothermal growth (LIHG) is developed for rapid, one step, digital selective growth of nanowire directly on 3D micro/nanostructures without using conventional photolithography or chemical vapor deposition. The LIHG process greatly reduces the process lead time and simplifies nanowire-based nanofabrication by removing multiple steps for growth, harvest, manipulation/placement, and integration of the nanowires. Furthermore, the LIHG process can grow nanowires directly on 3D micro/nano structures.

Controllable adhesion to glass spheres with a new magnetically actuated synthetic gecko adhesive made from a magnetoelastomer is demonstrated. Adhesion is controlled by orienting the microfabricated surface features with an external magnetic field. Results show sphere pull-off forces can be increased 10-fold by changing the ridge orientation. Applications include solar panel cleaning, reusable adhesives, and microfabrication.

Ga occupies both the void and Sb sites in CoSb₃ which is proven by combining first-principles calculations and experiments. The stabilization of the Ga impurity as a compound defect extends the region of skutterudite phase stability toward Ga_0.15Co₄Sb_11.95 whereas the solid–solution region becomes much smaller in other directions of the phase diagram. This compensated defect complex leads to a nearly intrinsic semiconductor with low carrier concentration, and therefore high thermopower, which possesses a much reduced lattice thermal conductivity.

The pH-responsive, smart polymeric nanocarrier (SPN) with matrix metalloproteinase (MMP)-7-dependent proximity-activated targeting (PAT) incorporates polyethylene glycol (PEG) shielding that is removable in MMP-7-rich environments (i.e., breast cancer metastases). The up-regulated MMP-7 activity in pathological tissue exposes the cationic component of the SPN polymer, triggering cell uptake. Following internalization of polymers into the endosomal pathway, pH-dependent endosomal escape facilitates cytosolic siRNA delivery.

A methodology to develop suspended structures with tunable Poisson's ratios is reported. Two-photon polymerization is used to fabricate suspended web structures with a negative Poisson's ratio (NPR), based on analytical models. This technique could be used to investigate effects of altering the Poisson's ratio of several photocurable biomaterials on a variety of cellular aspects including morphology, gene expression, and migration using different cell types.

The application of time-resolved photoluminescence and fluorescence lifetime imaging for heparin sensing and bioimaging based on phosphorescent conjugated polyelectrolytes (PCPEs) containing iridium(III) complexes to eliminate background fluorescence with enhanced signal-to-noise ratio is reported.

A large magnetoresistance effect in conventional silicon p–n junctions is reported. By utilizing the magnetic field to manipulate the space-charge region of the p–n junction, a 2500% magnetoresistance ratio is observed at room temperature with H = 5 T. The p–n junction controlled by both electric field and magnetic field will open a new avenue for future magneto-electronics.

Efficient persistent room temperature phosphorescence with a quantum efficiency of greater than 10% and a lifetime longer than 1 s from pure organic amorphous host-guest materials is demonstrated in air. Physical rigidity and oxygen blocking characteristics of amorphous steroidal compounds as the host greatly minimize quenching of long-lifetime triplet exitons of the guest by interaction with the host and oxygen.

A high-performance graphene oxide (GO)-doped ion gel is developed, which may have great potential for applications in wearable energy storage devices. This GO-doped ion gel demonstrates significantly improved ionic conductivity compared with that of pure ion gel, due to the homogeneously distributed GO as a 3D network throughout the ion gel by acting like an ion “highway”.

Micro-optical components, ranging from microprism and microlens arrays, to diffraction gratings, and holograms are fabricated from a semi-crystalline shape memory elastomer. These resulting components represent a class of micro-optical devices with programmable optical properties. Spatio-selective manipulation of these optical devices can be further achieved by the integration of individually addressable arrays of microheaters.

Poly (dimethylsiloxane) (PDMS) is used to fabricate micro-structured complementary surfaces by molding into a silicon master with micro-channel profiles patterned by photolithography. For each pair of complementary surfaces, dislocation defects are observed in the form of visible striations, and misalignment angle is found to be the key factor controlling dislocation distribution and adhesion strength. The ability to control the orientation and periodicity of dislocation patterns by changing misalignment angle makes this system eminently controllable.

Dye-sensitized solar cells (DSSCs) combining Zn₂SnO₄ fiber-based photoelectrodes and purely organic sensitizers are fabricated. The highly porous amorphous Zn₂SnO₄ electrodes are prepared using electrospinning techniques and combined with a new organic dye. Using this strategy, devices that show photovoltaic conversion up to 3.7% are produced. The results rank among the highest reported for devices using ternary metal oxide sensitized electrodes.

The effect of SmCo₅ nanoparticle dispersion in a carbon matrix on the coercivity is investigated. Poor dispersion of these nanoparticles results in a moderate room temperature coercivity of ≈1 kOe. By increasing the inter-particle distance substantially, coercivity increases up to 12 kOe due to the overall anisotropy increase with the decrease in exchange interactions according to the random anisotropy model.

Nanorod arrays of functionalized poly(3,4-ethylenedioxythiophene) (PEDOT) are assembled by using an anodic alumium oxide template directly fabricated on gold-coated silicon wafers. These nanorod arrays are promising for organic electronic and biomedical applications. This approach allows a platform to understand the molecular and nanostructural effect on the surface wettability of these materials.

Water resistant, in situ crosslinked gelatin nanofibers are produced in a versatile one-step electrospinning process, using glyoxal as a crosslinking agent. The slowly progressing crosslinking reaction during electrospinning increases the solution viscosity and the average fiber diameter, thus forming gradient nonwovens. To improve the mechanical stability, we laminate the crosslinked gelatin nonwovens with perforated polycaprolactone layers.

Model of charge separation from polymer singlet excitons, including both interfacial charge-transfer (CT) states, loosely bound polaron pairs and dissociated polarons. For blend films where at least one material is relatively crystalline, efficient dissociation of photogenerated polarons is observed. For amorphous blend films, significant recombination of loosely bound polaron pairs is observed on the 100 ns timescale.

A Cu₂O-based solar cell synthesized using atmospheric atomic layer deposition (AALD) and employing a back surface field architecture is demonstrated for the first time. Enhanced charge collection is observed when a layer of AALD Cu₂O⁺ is overlaid on electrodeposited ZnO/Cu₂O layers. These cells produce a record short circuit current density of >6.3 mA cm⁻² for a fully-atmospherically deposited ZnO/Cu₂O device.

A new method is described for patterning microbubbles on cell monolayers to target ultrasound treatment to cells. This novel platform provides a controlled system for high throughput testing of the effects of ultrasound-mediated cell membrane disruption on cell physiology. Using this patterning method, it is possible to induce apoptosis in select populations of cells.

A new series of organic sulfide mediators with programmable redox properties is synthesized for efficient dye-sensitized solar cells (DSCs) through simple structural modification. Furthermore, addition of graphene components into the normal carbon counter electrode material can dramatically improve the catalytic activity of the counter electrode towards these sulfide mediators, giving the DSCs formed using these organic mediators good conversion efficiency.

A novel copper/graphene composite anode is proposed and applied as the anode of a top-emission organic light-emitting diode without any graphene transfer process. The maxima of current and power efficiency of a typical copper/graphene composite anode device reach 6.1 cd/A and 7.6 lm/W, respectively, which are markedly higher than those of the control devices with a graphene anode or an ITO anode.

A multifunction polymerizable ionic liquid, diallyldimethylammonium tetrafluoroborate, is used in a one-pot synthesis of novel luminescent polymer-nanoparticle composites. Small monodisperse lanthanide fluoride nanoparticles are formed by microwave irradiation in the presence of Ln(OAc)₃·xH₂O (Ln = Gd, Eu, Tb, OAc = acetate) in the ionic liquid. Irradiation under high intensity UV gives colorless, processable polymer materials with good photophysical properties.

Smart charge-reversible upconversion nanoparticles are developed for pH-responsive in vivo near-infrared light -excited photodynamic therapy. While stable under normal physiological pH, highly sensitive acid-induced charge conversion of those nanoparticles is observed in slightly acidic tumor microenvironments, resulting in significantly enhanced cellular internalization of nanoparticles and remarkably improved photodynamic cancer-cell killing efficacy.

A new greenish-yellow emitter is synthesized and a novel device concept is introduced featuring interzone exciton transfer to achieve unprecedented performance: external quantum efficiencies (current efficiencies) of 21.5% (77.4 cd/A) and 20.2% (72.8 cd/A) at 1000 cd/m² and 5000 cd/m², respectively, for greenish-yellow emitting phosphorescent organic light-emitting diodes, excellent for displays and solid-state lighting.

Semi-ionically fluorinated graphene has good insulating properties. After selective elimination of ionic C–F bonds, s-FG recovers in current by a factor of 10⁹, from 10⁻¹³ to 10⁻⁴ A. The fluorination and reduction processes permit the safe and facile non-destructive property control of the s-FG film.

Encapsulation of Fe phases inside multiwalled carbon nanotubes (MWCNTs) allows isolating reactive magnetic phases exerting magnetic fluid hyperthermia responses. In particular, bioconjugation of Fe@MWCNTs with monoclonal antibody Cetuximab enables the selective in vitro cancer cell sorting and stimuli-induced cytotoxicity under application of external magnetic inputs. Molecular dynamics calculations shed further light on binding modes and conformational properties of the Ab moieties linked on to the tubular carbon framework.

Poly(methyl methacrylate) (PMMA) brushes are demonstrated for the first time as electrets. Micro/nano patterns of electrostatic charges are fabricated on PMMA brushes by conductive microcontact printing and AFM lithography. The electrostatic charges on PMMA brushes are stable enough in organic solvents for guiding the assembly of nanoparticles and directing the dewetting of bulk polymer thin films.

Functional biomaterials with a 3D porous architecture are a requirement for biomimetic scaffolds for skeletal tissue remodeling. Microarrays of ternary polymer blends are fabricated and screened, resulting in the generation of structural and functional 3D biomimetic scaffolds capable of directing skeletal tissue formation.

Silk fibroin is investigated as a novel material for fabricating brain-penetrating electrodes with dynamic mechanical properties and the capacity to deliver sensitive therapeutics. Silk coatings are shown to natively reduce some markers of gliosis in vitro, and a further reduction is demonstrated by encapsulation and release of the enzyme chondroitinase ABC.

Microstructured liquid crystalline elastomer surfaces covered with micropillar arrays are developed using a replica molding technique. When modulating the temperature, the contraction of the pillars along their long axis induces a roughness change and therefore a change of the wetting properties of the microstructured surfaces.

The photochemical monomer-to-dimer transformation of the fullerene [6,6′]-phenyl-C₆₁-butyric acid methyl ester (PCBM) is strongly dependent on the light intensity. This is utilized to realize sub-second UV-light induced patterning of electronically active PCBM films. Dimer formation takes place between two monomers photo-excited to the triplet state. These findings challenge the conventional wisdom in the field.

A novel and economic water-soluble sacrificial salt-crystal-template process is developed for the large-scale production of hollow Ag@AgCl cage materials. The hollow Ag@AgCl cages show superior photocatalytic performance (28 times larger) compared with the solid form, which profits from the highly efficient electron-hole pair separation that results from ultrafast plasmon-induced electron transfer from Ag nanoparticles to the AgCl surface.

The contact resistance in organic thin-film transistors is affected by many more parameters than just the injection barrier at the metal/organic interface. The arrangement of the electrodes, the operation conditions, as well as the carrier mobility can change the contact resistance by many orders of magnitude. This can be understood from the details of the potential distribution in the devices.

The effect of cation stoichiometry and substrate defect density on nucleation, structure, defect formation, and interfacial mixing during III-III perovskite complex oxide heteroepitaxy is explored. Cation imbalance is shown to result in anti-site defect formation within the film, and subsurface cation vacancies promote cation mixing.

A new bipolar host molecule (CzFCN) configuring hole-transporting carbazole and electron-transporting cyano-substituted fluorene via a saturated carbon center is utilized to realize highly efficient electrophosphorescent blue, green, yellowish-green, yellow, red, and white devices using a common device structure.

The quantum yield (QY) of CdSe/CdS core/shell colloidal quantum dots (QD) is reduced exponentially with increasing electric field (F_qd). This reduction is more pronounced with thicker shells and is due to the reduced overlap between electron and hole wavefunctions. This has strong implications for the use of QDs in opto-electronic applications, where electric field strengths can readily exceed 1 MV cm⁻¹.

A new type of nanostructured selective ultraviolet reflecting mirrors based on the alternated deposition of layers of SiO₂ and ZrO₂ nanoparticles is presented. The UV blocking effect arises exclusively from optical interference phenomena and depends only on the number of stacked layers and the refractive index contrast between them.

An ion-exchanged glass is introduced as a new substrate that is not only virtually unbreakable therefore overcoming the brittleness that Si wafers possess, but also allows fabrication of high performance organic electronic devices. The smoothness of the surface of this fusion-drawn glass enables favorable large grain growth of the semiconductor, enabling high charge carrier mobilities of all kinds of organic semiconductors like pentacene or C60.

Transient electronics are designed to be stable and fully functional during their lifetimes, but then completely disappear in water or biofluids at prescribed rates and at programmed times. Analytical models are established for the dissolution of constituent materials in transient electronic systems, and they provide important design tools for transient electronics.

A giant electrocaloric effect at room temperature is obtained in coexisting antiferroelectric and ferroelectric phase relaxor Pb_0.8Ba_0.2ZrO₃ thin films. Such an effect is usually obtained only at the Curie temperature. This is therefore a promising material for applications in cooling systems near room temperature.

High-aspect-ratio responsive cilia arrays that combine, in one system, sensing and motility functions are fabricated. Based on different approaches the system can be electrically, environmentally or magnetically activated. Detection of changes in environment, such as a decrease in pH, triggers a collective cilia response, to an external time-dependent magnetic field.

Polymer electrolyte films are deposited onto highly porous electrospun mats using layer-by-layer (LbL) processing to fabricate composite proton conducting membranes. Various dip and spray processing techniques are investigated for different and unique composite film morphologies. By combining the different spray-LbL fabrication techniques with electrospun fiber supports and tuning the parameters, mechanically stable membranes with high selectivity can be produced.

A molecular imprinting technique is introduced into a lab-on-paper device through electropolymerization of molecularly imprinted polymer in a novel Au nanoparticle (AuNP) modified paper working electrode. This is fabricated through the growth of AuNP layers on the surfaces of cellulose fibers to enhance the conductivity of the cellulose fibers in the paper and, as a result, increase the effective surface area of the electrode.

Dense integration of interfacial ferromagnetic centers in the lamellar structure gives enhanced ferromagnetism to ZnO nanosheets. Anion exchange with dodecyl phosphate layers strongly suppresses ferromagnetic ordering as a result of surface defect passivation while maintaining bulk-like n-type semiconducting properties.

A facile strategy to create free-standing graphene honeycomb films is developed. The obtained free-standing honeycomb films can be easily transferred to the substrate of interest while retaining their original sizes and structures, and exhibiting broad spectrum antibacterial activity and enhanced efficiency of photoconversion.

The effects of molecular intercalation and thermal annealing are described on active layer cohesion in organic photovoltaics with the donor polymer poly(3,3″′-didocecyl quaterthiophene) (PQT-12). Increased cohesion is related to the extent of intercalation and the presence of fracture resistant domains. Correlation with annealing and device efficiency is presented.

Ferroelectric polymer [P(VDF-TrFE)] free-standing nanodot arrays with ultrahigh data storage density are fabricated through nano-imprinting. The preferred orientation of the copolymer chains in the nanodot arrays is favorable for polarization switching of single nanodots. This approach allows nanometer electronic features to be written directly in two dimensions by piezoresponse force microscopy probe based technology.

A rapid, facile, and inexpensive method to fabricate hierarchically structured gold electrodes that present high surface areas is presented. The combination of vinyl film masking, stress-driven wrinkling, and electrodeposition allows the rapid prototyping of electrode designs. The fabricated electrodes are robust, highly reproducible, perform well in electrochemical measurements, and demonstrate up to 1000% enhancements in electroactive surface area.

The design of hybrid organic−inorganic membranes using an electrospinning approach is discussed. The sulfonated silica-based membranes exhibit proton conductivity comparable to Nafion at high temperature and low humidity and have better mechanical properties. This behavior is related to the specific microstructure of the membrane, which is reached via the electrospinning. The membrane contains polymer fibers surrounded by functionalized large silica domains.

2,1,3-benzothiadiazole (BT) units are systematically incorporated into star-shaped trigonal molecules comprising a truxene core and three quaterfluorene arms. Five isomers are synthesized corresponding to the symmetric insertion of a single BT unit into each of the possible positions within the arms. Three BT locations are identified (see figure) by comparison of absorption and photoluminescence (PL) spectra, supported by theoretical calculations. Additional experimental and theoretical characterizations reveal the influence of BT position on Raman, photoluminescence, and stimulated emission properties.

All-inorganic, transparent n-type transistors are deposited by means of the solution processing technique of chemical spray pyrolysis. The use of different precursors leads to semiconducting, conducting, and insulating materials, which are patterned with a simple stencil mask technique during the spray process, thus realizing fully functional devices. Optical, electrical and microstructural properties are investigated.

An amphiphilic design and solution-state self-assembly of π-conjugated systems results in free-standing, nanostructured sheets with green fluorescence. Highly ordered, lamellar molecular organization in the sheets leads to good mobility when transferred on to a field-effect transistor device.

Based on a combination of surface acidification and sonication-promoted insertion, an optimized and general synthetic strategy is established for the templated construction of polymeric carbon nitride nanoarchitectures with maximized material and structure functions.

Learning from nature has inspired the invention of intelligent materials and devices. Inspiration from the retina, which can serve as a light-driven cross-membrane proton pump, a photoelectric conversion system based on smart gating hydroxide ion-driven nanochannels and photoinduced reversible pH changes is demonstrated. This photoelectric conversion system closely mimics the mechanism of the retina and shows potential applications for future energy demands.

Cofacial π-orbital interactions between the fullerene and the cyclobutene addend are shown to decrease the electron affinity and thereby increase the lowest unoccupied molecular orbital (LUMO) energy level of C₆₀ significantly. The increased LUMO level of fullerene can be used to generate higher open-circuit voltages and a comparable power conversion efficiency relative to the widely used P3HT/PCBM composite.

A straightforward technique for fabricating autonomic, hetero-structured hydrogels is presented. These gels represent a novel composite concept involving internally responsive and autonomous constituent materials. Critical design parameters are established and a basic modeling approach and material functionality are demonstrated through a coupled patch actuator.

Dynamic mineralization in the radular teeth of Cryptochiton stelleri, investigated via microscopic and spectroscopic methods, initiates via the templated synthesis of ferrihydrite crystal aggregates along an α-chitin matrix. These aggregates subsequently transform to magnetite via a solid-state phase transformation, followed by magnetite crystal growth, which yields highly oriented nanorods that exhibit regionally defined geometries affecting the mechanical properties of the mature teeth.

A DNase I coating using dopamine as an intermediate layer, strongly reduces bacterial adhesion and prevents biofilm formation by degradation of eDNA in the biofilm matrix causing disruption of the matrix that holds the biofilm together, without affecting mammalian cell adhesion and proliferation.

By replacing poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) hole-transporting layers (HTLs) with solution-processed nickel oxide (NiO), polymer photovoltaic cells with a power conversion efficiency of 7.8% are fabricated. Solar cells with NiO are more efficient and more air stable than those with PEDOT:PSS. The HTL/active layer interface plays a critical role in solar cell performance.

Polymer brushes created by self-initiated photografting and photopolymerization provide a straightforward route for the biofunctionalization of bioelectronic devices, where a high loading and stable immobilization of biomolecules as well as a biocompatible environment and efficient charge transfer are essential. In this report the potential of this approach is demonstrated by the example of amperometric glucose sensing with glucose oxidase- and ferrocene-functionalized poly(methacrylic acid) brushes on nanocrystalline diamond electrodes.

The first example of the solid-phase synthesis of MIP nanoparticles is reported using an immobilized template in an automated reactor. Formation of nanoMIP by photopolymerization in a column packed with the template phase is followed by washing to remove low affinity particles. High temperature elution releases the high affinity nanoMIPs and the template phase, which can be re-used.

The dynamic mechanical compression of continuously reinforced carbon nanotube (CNT)/poly(dimethylsiloxane) composites provides insight into the mechanics of deformation in nanocomposite systems. Loaded along the nanotube axis, these composites respond similar to open-cell forms due to a collective buckling of the CNTs. Compressed normal to nanotube alignment, the CNTs will effectively augment the cross-link density of the elastomer network, lowering the ultimate compressive strain.

Different thicknesses of TiO₂ are deposited by atomic layer deposition on SiO₂ mesoporous templates and a critical thickness for the efficient collection of the photogenerated charge carriers in dye sensitized solar cells is identified. This work presents an alternative photoanode with one order of magnitude higher transport rate compared to the conventional nanoparticle titanium dioxide mesoporous films.

An optical, irreversible temperature sensor is fabricated based on a chiral-nematic polymer network that has an orange reflection color. After mechanical embossing of the polymer film a temporary shift to a green color is achieved, which shifts back to the original color above a certain threshold temperature. This sensor can be printed on a foil, thus displaying its potential application as a battery-free time-temperature integrator in food and pharmaceutical products.

A topographically flat and laterally homogeneous silica surface with embedded metallic nanostructures is fabricated using a template-stripping technique to interface biomembranes with tunable plasmonic fields for label-free optical biosensing and imaging.

Metallic-glasses are promising for electrocatalytic applications due to their favorable chemistry and unique abilities for thermoplastic manipulation down to the nanometer length-scale. Combination of electrochemical processing and thermoplastic nanofabrication of metallic glasses serves as a versatile toolbox for fabricating hierarchical metallic nanostructures with large surface area and tunable morphology.

The electrocaloric effect (ECE) is investigated in a dielectric liquid. By exploiting the large dielectric anisotropy in a liquid crystal, 5CB, that facilitates the electric-field-induced large polarization change, a large ECE is observed near 39 °C, the nematic-isotropic transition temperature region. Fluidic ECE materials could lead to easier and better design of ECE-based cooling devices.

Inspired by superhydrophobic self-cleaning lotus leaves and porous biomaterials, polyurethane foam with simultaneous superhydrophobicity and superoleophilicity is fabricated. The resulting foam exhibits super-repellency towards corrosive liquids, self-cleaning, and oil/water separation properties, thus possessing multifunction integration.

Successful alignment control of the B4 helical nanofilament assembly in a binary mixture system of bent-shaped and rod-shaped liquid crystals is presented. The aligned nanofilament domains appear as extremely smooth and uniform stripes over millimeters. Second-harmonic generation (SHG) studies including a new technique, interferometric SHG microscopy, reveal that in these aligned domains, polarity from the nucleus and chirality are preserved.

Tremendous improvement in rectifying performance is predicted by calculations for donor–acceptor molecular devices with odd numbers of carbon atom chains that act as spacers, to predicted values that are much higher than in all previous studies. A dramatic odd–even oscillation effect is also shown for the current rectification and negative differential resistance with increasing carbon-chain length.

A methodology for controlled in situ reduction of spin-cast graphene oxide nanometric films on flexible substrates and the subsequent realization of highly conductive and transparent electrodes for flexible organic photovoltaic devices is presented. The technique is compatible with temperature-sensitive substrates in the sense that it achieves reduction of films on flexible substrates in a single step.

A broadband absorption of organic solar cells (OSCs) is realized by combining differently shaped nanomaterials exhibiting varied localized plasmonic resonances and scattering regions into the active layer. As a result, power conversion efficiency is enhanced by 19.44% compared to pre-optimized control OSCs. With respect to the origin of this enhancement, our theoretical and experimental studies show that the broadband resonance is achieved by the simultaneous excitation of versatile plasmonic resonances, i.e., material-, shape-, size-, and polarization-dependent low- and high-order plasmonic resonances.

PbSe core and PbSe/PbS core/shell quantum dots (QDs) are employed in a QD/TiO₂ heterojunction solar cell. Theoretical calculations show that the wave functions of electrons and holes are extended to both materials, which contribute to the better photovoltaic performance of the PbSe/PbS core/shell than the PbSe core. The PbSe/PbS core/shell heterojunction solar cell produces a power conversion efficiency of 3.93%.

Single-crystalline p-type Zn₃As₂ nanowires are successfully synthesized and used as building blocks for high-performance field-effect transistors and photodetectors. By using a contact printing process, highly aligned nanowire arrays are produced to fabricate thin-film transistors and photodetectors on both rigid and flexible substrates.

Surface-active hierarchically porous monoliths consisting of hydrogen silsesquioxane (HSiO_1.5) are prepared via sol-gel accompanied by phase separation. The on-site reduction of aqueous noble metal salts results in the formation and embedding of metal nanoparticles throughout the monoliths. Both the bare monolith and nanoparticle-embedded monolith are promising as reusable and recyclable heterogeneous catalyst.

Alkaline amino acids of arginine-, histidine-, and lysine-modified chitosans (AAA-CSs) are designed for use as nonviral gene vectors and synthesized to simulate the components of viral envelopes. The DNA condensation capacity and intracellular tracking of the AAA-CSs are investigated. Arginine-modified chitosan exhibited the best cellular internalization and gene-transfection efficiency both in vitro and in vivo.

Two coordination complexes with deep blue emission, small singlet–triplet splitting, and ambipolar transport properties are designed and synthesized. Efficient electroluminescent devices with the three primary colors are achieved by employing the complexes as an undoped deep-blue emitter in organic light-emitting devices (OLEDs) and as a host in red and green phosphorescent OLEDs.

A sensationally-warm but physically-cold candle light-style emission driven by electricity is developed in lieu of hydrocarbon-burning in the energy-inefficient, greenhouse gas releasing candles invented 5000 years ago. The dimmable and single-sided emitting nature of the developed candle light-style organic light emitting diode (OLED) provides a lighting atmosphere free from glare and obtrusion.

Three types of layered α-Co(OH)₂ nanocones with intercalated anions of dodecyl sulfate, benzoate, and nitrate, corresponding to interlayer spacings of 1.6, 0.7, and 0.09 nm, respectively, are prepared and used as model materials to investigate the effect of interlayer space on the electrochemical activity in the system of α-Co(OH)₂ nanocone-based pseudocapacitors.