Materials Nanoarchitectonics for Advanced Physics Research

Nanoarchitectonics combines nanotechnology with existing fields such as organic chemistry, supramolecular chemistry, materials science, microfabrication, and bio‐chemistry. It is a concept to create the architecture of atoms, molecules, nanomaterials, and other units for use in functional material systems through various processes. Structural control through nanoarchitectonics can contribute to a variety of fields for advanced physical research. New physical properties can be controlled by forming atomic arrangements, molecular designs, polymer syntheses, crystal structures, self‐assembled structures, and superstructures. Construction of nanospace structures can also elucidate the specific physical properties of molecules trapped in them. Thus, nanoarchitectonics has great potential to contribute to advanced physical research. This paper will discuss some perspectives, categorizing the examples into those that focus on structure formation, those related to optical and photonic functions, those that exploit electronic and electrical properties, and those oriented toward device applications. The presented examples ensure significant contribution of nanoarchitectonics to advanced physical research.


DOI: 10.1002/apxr.202200113
has become clear that in addition to the properties of the materials themselves, control of their structures is also important in demonstrating their functions. [5][6][7] In particular, the structure at the nano-level greatly influences the properties of the materials. This has become clear due to the development of nanotechnology since the later period of the 20th century. Nanotechnology has enabled direct observation of atomic and molecular structures, [8,9] their dynamic behaviors, [10,11] and evaluation of physical properties at the nanoscopic level, [12,13] which has dramatically advanced our understanding of nano-level functions and properties. As the next stage of development, it is important to apply nano-related knowledge to material chemistry and related physics. As a post-nanotechnology concept, [14] nanoarchitectonics was proposed by Masakazu Aono in the beginning 21st century, [15,16] just as Richard Feynman founded nanotechnology in the 20th century. [17,18] Nanoarchitectonics combines nanotechnology with existing fields such as organic chemistry, supramolecular chemistry, materials science, microfabrication, and bio-chemistry. [19,20] It is the concept for architecture of atoms, molecules, nanomaterials, and other units into functional material systems through various processes (Figure 1). Preparation of materials in nanoarchitectonics methodology is achieved by selecting and combining unit processes such as chemical and physical transformation, atomic and molecular manipulation, self-assembly and selforganization, arrangement control by external fields and forces, nano-and microfabrication, and biochemical processes. [21] Since all the matter are essentially composed of atoms and molecules, this methodology applies to all the matter in principle. Therefore, analogous to the theory of everything in physics, [22] nanoarchitectonics may be said to be the method for everything in material science. [23] Material architecture in nanoarchitectonics uses various processes, including equilibrium and nonequilibrium processes. For example, it combines molecular assembly, [24][25][26] material transformation, [27][28][29] thin film techniques such as Langmuir-Blodgett (LB) method [30][31][32] and layer-by-layer (LbL) assembly [33,34] and microfabrication techniques. [35,36] Unlike conventional self-assembly, which relies on equilibrium simple processes, nanoarchitectonics is well suited for creating asymmetric and/or hierarchical structures. [37] In addition, nano-level phenomena often include nano-specific effects such as thermal fluctuations, statistical distributions, quantum effects, and other uncertainties. Nanoarchitectonics also incorporates such uncertainties to architect materials. [38] The above features of structure construction methods give nanoarchitectonics a place to study simple and fundamental nanophenomena as well as advanced nanofunctions that are assembled by linking them together.
The concept of nanoarchitectonics can be applied to various fields from basic to applied. The nanoarchitectonics approaches are used in chemistry such as material synthesis, [39,40] structure control, [41,42] and catalysis, [43,44] in biology such as basic biochemistry [45,46] and biomedical sciences, [47,48] in functional instrumental systems such as sensors [49,50] and devices, [51,52] and in practical applications such as the environment applications [53,54] and energy applications. [55,56] Although many of these may appear to be chemistry or biology in nature, the underlying phenomena are based on physical principles. Therefore, the concept of nanoarchitectonics can serve as a foundation for the exploration of physical phenomena. In order to elucidate physical phenomena, the control of the target structure becomes essential. In addition to existing structures, it is also necessary to artificially build the desired structures. Accordingly, nanoarchitectonics can provide the foundation for advanced physical research. This paper highlights examples from recent research reports on physics-oriented research and the creation of nanostructures for measuring physical properties, which set forth the concept of nanoarchitectonics. They are not all-encompassing, but they provide an insight into trends and characteristics. This paper will discuss some perspectives, categorizing the examples into those that focus on structure formation, those related to optical and photonic functions, those that exploit electronic and electrical properties, and those oriented toward device applications. Through those examples, the possible contribution of the concept of nanoarchitectonics to advanced physical research will be discussed.

Nanoarchitectonics in Structural Organization for Physics Research, General
Various physical phenomena depend on the precise arrangement of functional components at the nanometer level. The connection between nanoarchitectonics and physics was described pioneeringly in Hecht's 2003 paper. [57] He states that in order to assemble individual building block atoms and molecules into the desired integrated system, it is important to establish multiple processes, including self-assembly of those molecules and immobilization Supraball: a solid-state three-dimensional superlattice-type spherical assembly of ferrite (Fe 3 O 4 ) hydrophobic nanocrystals. Reproduced with permission. [60] Copyright 2022, Royal Society of Chemistry. by substrate activation. Yoshida, Yamashita, and co-workers are studying complexes between lanthanides and other metals as nanoarchitectonics at the atomic level. [58] Lanthanide compounds are common research targets in the fields of magnetism and optics due to their electrons localized in the f-orbital. They have computationally determined the role of metal-organic ligands in the electronic and magnetic properties of lanthanide complexes. In particular, slow magnetization relaxation in the Pt-Gd-Pt system was observed up to 45 K, a high temperature among isolated Gd-based complexes. The absence of low-energy vibrational modes favors the slow magnetization relaxation at high temperatures. Thus, the nanoarchitectonics of the complexes is important for the control of magnetic properties.
As a way to control physical properties by controlling the crystal lattice, Liu and co-workers investigated the pressure dependence of barium halide crystals under the concept of high pressure nanoarchitectonics. [59] Under normal pressure, BaCl 2 has a cubic structure with Fm-3m symmetry and BaBr 2 has an orthorhombic structure with Pnma symmetry. Under high pressure, BaCl 2 and BaBr 2 take on an orthorhombic Cmcm symmetric structure, especially at 74 and 47 GPa, respectively. Simulations show that this crystal structure exhibits metallic features under high pressure. In high pressure nanoarchitectonics, the electronic state changes with pressure, and localized electrons become delocalized, resulting in band broadening. This leads to metallization. Pileni reported nanoarchitectonics of a solid-state three-dimensional superlattice type called supraball (Figure 2). [60] It is a solid spherical assembly of ferrite (Fe 3 O 4 ) hydrophobic nanocrystals. This superball superstructure functions as a photonic crystal. The supraball acts as a nano-heater when illuminated with light. The photothermal effect can also induce tumor necrosis associated with laser irradiation. Such supraball nanoarchitectonics could contribute to a wide range of science and technology, from colloid chemistry and soft matter physics to power technology, pharmaceuticals, and food science.
Molecules trapped in special nanospaces often exhibit unique physical properties. The architecture of such nanospaces is another contribution to physical research through nanoarchitectonics. Kobayashi et al. constructed one-dimensional nanochannels using tris(o-phenylenedioxy)cyclotriphosphazene and observed that organic radicals of different sizes that were trapped in 4-oxo-2,2,6,6-tetramethyl-1-piperidinyl-1-oxyl molecular chain were investigated by temperature-variable electron spin resonance. [61] Spin interactions of organic radical onedimensional molecular chains formed in nanochannels are affected by the size, dynamics, and temperature of the guest molecules. It is found that one-dimensional spin diffusion is enhanced at low temperatures in size-tunable nanochannels. Such nanoarchitectonics-based physical studies will be useful for the design and development of new organic magnets. Metalorganic frameworks (MOFs) are a prime example of supramolecular structures that can architect such nanospaces. Miyasaka discusses the properties of electron-coupled, charge-transfer MOF structures consisting of an electron donor and an electron acceptor in his recent review. [62] He showed the possibility to tailor the charge by controlling the electron-conjugated charge transfer in the lattice between the electron donor and the electron acceptor to produce various charge distributions. By selecting the coordination building blocks, it is possible to construct a wide variety of structures such as those shown in Figure 3. These controlled charge distributions and structures can modulate the responsiveness to physical stimuli such as temperature, pressure, and electric fields, as well as chemical stimuli including host-guest interactions. These responsivities depend on the HOMO/LUMO energy and the coordination properties of the unit. The physical properties of polymers can also be investigated in the nanospace formed by the inner pores of MOFs. In their recent review, Hosono and Uemura describe the possibility of polymer trap nanoarchitectonics, [63] in which the MOF backbone and the encapsulated polymers exhibit not only localized host-guest interactions but also the property of forming uncoiled chains, which is not the natural conformation of polymers. They are greatly affected by the structural constraints imposed by the nanopore space. As a result, the physical and chemical properties are greatly affected. More specifically, it provides a venue for the elucidation of physical phenomena that would not be observable in free space.
The structural control by nanoarchitectonics offers many possibilities for physical research. New physical properties can be controlled by forming structures such as atomic arrangements, crystal structures, and superstructures. The construction of nanospace structures provides an opportunity to elucidate the specific physical properties of molecules trapped in them. Thus, from an overview perspective, nanoarchitectonics has great potential to contribute to advanced physical research. The following sections will explore the potential contribution of nanoarchitectonics to advanced physics research from the specific viewpoint of optical and photonic properties, electronic and electrical properties, and device design based on these properties.

Nanoarchitectonics in Optical and Photonic Research
The optical and photonic properties of an object are highly dependent on the interconnections of light-responsive components. The design of photo-functional molecules and nanomaterials, Figure 3. A wide variety of structures with the electron-conjugated charge transfer in the lattice between the electron donor and the electron acceptor coordination building blocks. Reproduced with permission. [62] Copyright 2021, Chemical Society of Japan.
their inter-arrangement and integration, and the fabrication of structures such as intentional nanofabrication are key. In other words, this is where nanoarchitectonics can show its strength. For example, circularly polarized light emission can be applied to various applications, e.g., photoelectric devices, chiroptic materials, three-dimensional displays, bioprobes, and information storage and processing. Circularly polarized luminescence is often controlled by the aggregation of optically active organic and organometallic compounds with chirality in crystals, liquid crystals, nanoparticles, fibrous structures, and films. Nishikawa and co-workers have investigated the optical properties of chiral perylene diimide derivatives by absorption spectra, and by steady-state  and time-resolved fluorescence spectroscopy. [64] These derivatives exhibit aggregation-induced circularly polarized emission in films. The deposited thin films show circular dichroism and circular polarized emission, indicating that the solid-state aggregation of chiral molecules is linked to their chiroptical properties. Theoretical calculations indicate that the chiral twisted aggregation of perylenediimide derivatives due to intermolecular -interactions is essential for the chiroptical properties in the solid state.
Naota and co-workers have achieved flexible control of circularly polarized luminescence with molecular aggregation nanoarchitectonics of an achiral trans(salicylaldiminato)platinum(II) complex (Figure 4). [65] Molecular aggregation structures exhibiting circularly polarized luminescence were fabricated by the aggregate formation of this platinum complex formed by vortex flow at the air-water interface. In this process, the sign and intensity of the circularly polarized emission can be precisely controlled by changing the direction and intensity of the vortex flow with a mechanical stirrer. The air-water interface is a promising field for the generation of vortex-induced supramolecular chirality. Under non-vortex flow conditions, the lamellar arrangement based on stacking of cross-shaped molecular units disperses the optical energy of the excited state due to weak intermolecular interactions in small aggregates, and no optical signal is emitted. Under suitable vortex flow conditions, hydrophilic coordination surfaces attach to the water surface and hydrophobic Nalkyl chains are aligned vertically on the water surface due to van der Waals forces. The helical twisting force of the vortex flow at the air-water interface forms two-dimensional aggregates with a chiral U-shaped structure in a velocity-controlled manner. The degree of twisting is controlled by the velocity of the vortex flow, which controls the intensity of the chirality of the twodimensional domains. This method provides a unique approach to the nanoarchitectonics of future functional luminescent materials and is a useful knowledge for application to functional devices.
The optical function of -conjugated molecules depends on the rigidity of their structures. Molecular nanoarchitectonics to control the rigidity of photofunctional molecules has also been investigated. Tsuji has developed carbonbridged oligo(phenylenevinylene) molecules, in which the molecular structure of phenylenevinylene is contracted by Figure 5. Carbon-bridged oligo(phenylenevinylene) molecules with rigid planar molecular structure suitable for expanding -conjugation and its ZnP-COPV-C 60 conjugate structure with photoinduced electron transfer property. Reproduced with permission. [66] Copyright 2022, Chemical Society of Japan.
intramolecular cross-linking with substituted methylene groups ( Figure 5). [66] Carbon-bridged oligo(phenylenevinylene) (COPV) has a rigid planar molecular structure suitable for expanding -conjugation. The result is excellent functionality and high stability. For example, in the ZnP-COPV-C 60 conjugate structure, photoinduced electron transfer occurs from ZnP to C 60 via the oligo(phenylenevinylene) bridge, giving charge-separated states. Notably, the carbon-bridged oligo(phenylenevinylene) molecules exhibit cryogenic phenomena at room temperature. The immobilization of the molecular structure with chemical nanoarchitectonics is a technique to achieve cryogenic conditions independent of temperature. Carbon cross-linking could be a strategy to develop cryogenic physics at room temperature. Ueda has developed a sustainable luminescent system through molecular nanoarchitectonics. [67] Fluorescence, phosphorescence, and photoluminescence typically decay within a second at most, according to the total relaxation rate constant of the excited state. Sustained luminescence is achieved when luminescent ions temporarily lose their carriers due to photoexcitation and these carriers are captured in a trap in the compound. The design of the carrier trap results in the gradual release of the captured carriers over a time scale of seconds to days. These carriers then migrate back to the luminescent center, resulting in continuous luminescence over an extremely long period of time (Figure 6). The sustained luminescence is based on the nanoarchitectonics of the electronic structure of the host compound, including lanthanide and transition metal ions. Fluorescent phosphors Figure 6. Sustained luminescence (persistent luminescence) achieved by carrier trap. Reproduced with permission. [67] Copyright 2021, Chemical Society of Japan.
can be designed. This research will lead to the development of superior persistent phosphors in the near future.
Control of optical properties by nanoarchitectonics of inorganic materials has also been reported. Inorganic -Fe 2 O 3 can add to its existing properties by adding the property of millimeterwave absorption to magnetic recording technology, thereby expanding the range of applications of -Fe 2 O 3 . Tokoro, Ohkoshi, and co-workers discuss in a recent review the spectroscopic studies of -Fe 2 O 3 in the frequency range from terahertz to millimeter-wave. [68] Although it is beneficial to reduce the size of magnetic particles to improve the signal-to-noise ratio of the device, thermal stability is compromised. To maintain thermal stability, it is necessary to nanoarchitectonically increase the magnetic anisotropy of the material. Using this approach, we propose focused millimeter-wave assisted magnetic recording. The -Fe 2 O 3 film magnetic pole reversal was confirmed by magnetic force microscopy measurements, indicating that the new recording method may be useful for increasing recording density in the big data era. For the development of nano-optical devices, nanoarchitectonics of gold nanoparticle assemblies that significantly enhance the photoelectric field is useful. Imura and coworkers reported integrated immobilization of gold nanoparticles at the water-organic solvent interface. [69] The optical properties of the nanoarchitectonized assemblies were investigated using two-photon induced emission and surface enhanced Raman scattering, demonstrating that surface modification of gold nanoparticles can finely control the optical field enhancement and chemical environment near the gold nanoparticle assemblies. Surface-modified gold nanoparticle assemblies fabricated at the interface are expected to amplify photochemical processes and provide tailor-made chemical reaction fields.
Nanopatterning and micropatterning of metal oxide materials are important processes in the development of electronic and optoelectronic devices. Kirscher et al. have, under the concept of nanoarchitectonics, developed a new process that relies on direct-write laser patterning in the deep UV region developed. [70] The process is based on the fabrication of photoluminescent microstructures by patterning ZnO under room temperature and atmospheric conditions (Figure 7). This is caused by the aggregation and insolubility of the ZnO nanocrystals. The exposed area corresponds to the negative resin. This direct laser-write integrated patterning route can achieve sub-micrometer resolution while maintaining the photoluminescence properties of the ZnO nanocrystals. This room-temperature nanoarchitectonics process is particularly useful for incorporating luminescent nanocrystals into complex devices because it does not require thermal posttreatment or etching. This technology will contribute to optoelectronic applications on flexible substrates.
As demonstrated by Yan, Zhao, and co-workers, the development of nano-and micro-level wavelength-division multiplexing structures can increase the data transmission capacity in optical communication technology without the need for additional fibers. [71] Figure 8 shows an image of a wavelength-division multiplexing structure constructed with ZnO and CdS nanowires. The CdS source nanowires show the behavior of simultaneous continuous-wave excitation. The two sources have good optical confinement such that the photoluminescence emission propagates with low loss to both ends. Red-shift is observed due to the re-absorption effect during light propagation. Increasing the overlap length between the ZnO source line and the waveguide improves the coupling efficiency of the UV light. Most of the emission from the light source is coupled to the waveguide and transmitted without optical loss. The performance of the nanoarchitectonically designed wavelength-division multiplexed transmission structure was evaluated with two light source lines excited simultaneously. Crystalline ZnO and CdS nanowires with smooth surfaces and end-faces make excellent waveguides and light sources due to their remarkable light confinement effect and strong band edge emission. Emission from different light sources can be directly coupled to the wires shared by the multiplexer. The propagated mixed signals would be separated by size-dependent distinct photon confinement in a wavelength multiplexing transmission structure and sent to a predefined output port. The nanoarchitectonic assembly of such nanoblocks is expected to lead to a variety of photonic devices with complex functions. Zhao, Yao, and co-workers have developed a photonic function-orientated nanoarchitectonics, and the importance of designing and synthesizing nanowire heterojunctions. [72] In nanophotonics, precise control of the geometrical properties, surface morphology, and material composition of the constituent materials is essential for improving photonic function. Rational material design and construction through nanoarchitectonics is essential for photonic devices with desired functions. Following nanoarchitectonics methodology, optimal nanowire heterojunctions can be synthesized as photonic components by combining different methods such as self-assembly, deposition, lithography, and manipulation. Such an approach is useful not only for the development of photonic devices, but also for fundamental physics such as the fundamental interaction between light and matter.
Functional structural systems in nature exhibit highly efficient functionality due to the skillful arrangement of their constituent elements. In natural photosynthetic systems, proteins and peptides are combined with functional dyes to form elegant selfassembled complexes. This is a very good example of nanoarchitectonics. Yan and co-workers have developed artificially designed peptide-based light harvesting complexes under the concept of biomimetic light-harvesting nanoarchitectonics. [73] They investigated the coordination of chromophore organization, light harvesting properties, and energy transfer in biomimetic complexes through the non-covalent bonding of peptides and chromophores. How well the light harvesting and energy transfer, a multi-step process, are coordinated is important for the light harvesting function. Energy transfer occurs through Förster resonance energy transfer, an exciton-binding system that depends on the conformation of the chromophore. To realize multifunctional artificial light harvesting complexes, self-assembled nanoarchitectonics of chromophores by peptides must be well designed. Furthermore, the functionality of artificial light harvesting complexes can be further enhanced by co-assembling multiple chromophores into a single peptide derivative nanostructure or by introducing heterogeneous aggregates of chromophores into a single system.

Nanoarchitectonics in Electric and Electronic Research
As with optical properties, nanostructure formation is a key factor for electric and electronic functions. However, since technologies such as micro-wiring fabrication have been well discussed, we will discuss below the design of molecular structures and arrangement of nanostructures, which are more in the flavor of materials nanoarchitectonics. For example, in the development of organic electronic materials, the synthesis and development of conjugated polymers is an object of attention as molecular nanoarchitectonics. In particular, the development of highly ordered polythiophenes with alkyl groups in the side chains has attracted much attention in high-performance organic electro-active materials, and many studies have been actually conducted. Nishino, Mori, and co-workers have shown that 3-alkylthiophenes and thiophene units with cyclic siloxane moieties. [74] They found that random copolymerization of 3-alkylthiophene and thiophene units with a cyclic siloxane moiety formed a corresponding statistical copolymer. It was shown that acid treatment of the resulting polymers with trifluoromethanesulfonic acid vapor promotes ring opening of the cyclic siloxane moieties to form a network. The formation of such a network makes the polymer film insoluble in both organic and aqueous solvents. Furthermore, acid treatment causes doping of the polythiophene main chain. This doping extends the -conjugation of the copolymer and increases the conductivity by a factor of about 1056. The resulting copolymers are also expected to have improved mechanical properties, such as elastic properties, due to the formation of siloxane bonds between the polymers. This is an example of how simple molecular nanoarchitectonics can lead to several functional enhancements.
Simple nanoarchitectonic structural changes can also dramatically control the conductivity of nanoparticle-assembled materials. Yoshida and Ogawa coated carbon black nanoparticles of several tens of nm in size with silica layers of controlled thickness (2 and 12 nm). [75] The nanoarchitectonized core-shell nanoparticles were grafted with methacryloxypropylsilyl groups and uniformly dispersed in a poly(methyl methacrylate) film (Figure 9). The conductivity of the hybrid films varied dramatically with the thickness of the silica layer of nanoparticles aggregated in them. Films with a 2 nm silica coating layer became conductive, with a volumetric conductivity 10 6 times greater than that of 12 nm silica-coated particles. Only a sixfold change in thickness, a structural factor, was enough to achieve a 10 6 -fold improvement in the physical property of conductivity. Hybrid and/or composite nanoarchitectonics between polymers and inorganic materials has been reported to control electrical properties in various ways. Under the concept of electrochemical nanoarchitectonics, Costa et al. synthesized a composite of poly(methyl methacrylate) containing a nanofiller (NiO) and investigated its electrochemical properties. [76] In electrochemical tests, capacities of the Adv. Physics Res. 2023, 2, 2200113 Figure 9. Core-shell nanoparticles of carbon black with silica shell grafted with methacryloxypropylsilyl groups and uniformly dispersed in a poly(methyl methacrylate) film in which only a sixfold change in thickness, a structural factor, was enough to achieve a 10 6 -fold improvement in the physical property of conductivity. Reproduced with permission. [75] Copyright 2022, Royal Society of Chemistry.
composites (NiO 1% and 5%) were measured in the range of 119-407 μF g −1 , respectively. The redox reaction is attributed to the NiO nanofiller added to the polymer. The performance of the nanocomposites, such as specific capacitance, is related to the amount of ceramic nanofiller inserted into the polymer matrix. This indicates that nanoarchitectonics factors such as the ratio of matrix to reinforcing nanofiller are key when considering applications such as electrodes for electronic devices. As a reflection of materials nanoarchitectonics in electrical properties, Qu, Sun, and co-workers used resistance matching materials nanoarchitectonics to improve power generation in water evaporation driven generators. [77] They constructed working and electrode materials from graphene oxide, reduced graphene oxide, and carbon nanotubes, and performed resistance matching between them. This allowed us to optimize the generator performance of a water evaporation driven generator.
Analytical and theoretical approaches to nanostructures and nanoarchitectural structures are also important. In particular, analytical investigation of the precise properties of electrode interfaces is crucial for understanding their electrochemical properties. For example, neutron reflectometry has been used to study the electric double layer of ionic liquids. Nishi et al. discuss further sensitivity to the interface structure. [78] Sensitivity enhancement can be obtained by further promoting rational material design, such as using thin metal films with controlled scatter-ing length density and thickness as electrodes. Neutron reflectometry using a materials nanoarchitectonics strategy has revealed the structure of ionic multilayers at the electrode interface of highly sensitive ionic liquids. The development of adsorbed cationic layers on the electrode and the associated overscreen formation were clearly observed as a potential-dependent behavior. Reshak and co-workers have demonstrated that nanoarchitectonics of n-type organic semiconductors, using density functional theory (DFT), time-dependent DFT, and Hartree-Fock calculations to evaluate specific features of acrylate-based n-type organic semiconductors. [79] Contour electron density surfaces and molecular electrostatic potential plots were also calculated using the gauge independent atomic orbital method. These analyses revealed the presence of an electron cloud around the semiconductor.
In order to observe discrete changes in electrical properties, it is important to limit the number of dopants available for electrochemical conversion to a finite number, as small as a few tens. Hasegawa and co-workers present an experimental and theoretical approach to manipulate the number of dopants in a solid electrolyte at the atomic level. [80] In this approach, -Ag 2+ S nanodots containing indeterminate excess Ag (Ag + ions and electrons) are used as a model system to demonstrate the control and discrete manipulation of dopants by varying the electrochemical potential. The actual experiments were performed using a Pt Figure 10. An approach to manipulate the number of dopants in a solid electrolyte at the atomic level performed using a Pt chip/vacuum gap/ -Ag 2+ S/Pt system, with the position of the Pt chip electrode and the potential on the system controlled by scanning tunneling microscope (STM). Reproduced with permission. [80] Copyright 2018, Wiley-VCH.
chip/vacuum gap/ -Ag 2+ S/Pt system, with the position of the Pt chip electrode and the potential on the system controlled by scanning tunneling microscope (STM) (Figure 10). The nanodot size made it possible to tune the number of non-stoichiometric defects that could be electrochemically altered. When the Ag 2+ S nanodot size was small enough, discrete deposition on an atomic scale was confirmed to be possible. A limited number of nonstoichiometric dopants enabled atomic deposition by widening the gap between adjacent levels of the electrochemical potential. Theoretical predictions agree well with experimental results for layer-by-layer manipulation, indicating that discrete control of electrical properties is possible. In particular, the cohesive energy term is the key factor controlling the ordered layer-by-layer deposition. The nanoarchitectonics factors of proper material selection and size design make this process possible. This is a contribution to the development of nanodevices that rely on single ion/atom transfer.

Nanoarchitectonics in Devise-Oriented Research
Finally, nanoarchitectonics also shows its power in physical research in areas closer to practical applications, such as devices and energy materials. They are also based on controls of materials nanoarchitectonics. As shown in Figure 11, mixed anion compounds containing multiple anion species in a single phase have unique coordination structures and crystal structures not found in single anion systems as summarized in a recent review article by Maeda, Kageyama, and co-workers. [81] Because of the unique crystal structure of mixed anion compounds, in which multiple anions are coordinated to a cation, new functions can be expressed in various fields of chemistry and physics, such as catalysts, batteries, and superconductors. It is expected to develop materials for such fields as photoelectrodes, phosphors, conductors, thermoelectric materials, secondary battery components, and photocatalysts. For example, the greatest advantage of mixed anion compounds as photocatalysts and photoelectrodes is their ability to utilize visible light. The introduction of p orbitals of anions with low electronegativity into metal oxide semiconductor hosts results in a smaller band gap of the oxide. This is a very powerful strategy to overcome the large band gap, which is a drawback of ordinary metal oxide photocatalysts. In phosphor materials, the excitation and emission wavelengths can be tuned by band control through anion mixing. Furthermore, mixed anionization has been shown to be effective in the development of fast ionic conductors. The physical properties and functions of mixed anion compounds can be rationally nanoarchitected according to symmetry breaking, binding energy differentiation, and band gap control caused by mixed anionization. Mixed anion compounds are expected to be further developed in terms of both applications and fundamentals, and physical studies and device development based on them are being promoted.
As an illustration of the importance of evaluation-related technologies oriented toward device applications, Sakaushi has published a review article entitled Science of Electrode Processes in the 21st century. [82] The science of electrode processes, especially the elucidation of microscopic mechanisms of electrode processes, is the key to providing technologies related to carbon neutrality, such as rechargeable batteries, fuel cell electric vehicles, and green hydrogen production. In addition to materials development through nanoarchitectonics, this will be aided by supercomputers, simulation theory of complex electrochemical reactions, and state-of-the-art characterization methods. The development of sustainable and inexpensive electrode materials for advancing electrochemical technologies will likely be the breakthrough for achieving carbon neutral technology. Development of device structures that allow sophisticated surface analysis will also contribute to the physics picture of nanoarchitectonics. Nishijima and Juodkazis have nanoarchitectonized metalinsulator-metal type metasurfaces and demonstrated coupling of light and molecular vibration modes (Figure 12). [83] They show how to control and optimize the IR absorption/emission coupling as a coupling of optical and molecular vibration modes. By tuning the composition of the dielectric layer of the metasurface, absorption can be tuned to couple most efficiently with the plasmon modes of the metasurface.  Metal-insulator-metal type metasurfaces for coupling of light and molecular vibration modes. Reproduced with permission. [83] Copyright 2022, Chemical Society of Japan.
As sensor nanoarchitectonics, Mia, Sun, and co-workers have built a high-performance all-optical visible light detector (Figure 13). [84] Visible light detectors are essential devices for optical microscopy and high-speed wireless visible light communications. Fiber-integrated freestanding nanowire devices have the advantage of long light-matter interaction length and fast response time. A hybrid coupler integrating one-dimensional C 60 nanowires and optical microfibers was formed, and a light source was connected at one end, while the other end was connected to an optical spectrum analyzer to measure the transmission spectrum over time. This device achieves fast response and fast recovery. Further device structures can be built by integrating Adv. Physics Res. 2023, 2, 2200113 Figure 13. A high-performance all-optical visible light detector with a hybrid coupler integrating one-dimensional C 60 nanowires and optical microfibers. Reproduced with permission. [84] Copyright 2022, Elsevier.
different forms of C 60 nanomaterials and various fiber optic devices for light detection. Under the concept of green nanoarchitectonics for next generation electronics devices, You and coworkers presented a method for building conductive microelectrodes on regenerated cellulose. [85] Recycled cellulosic materials, a biomass resource, are widely used for various applications due to their degradability, sustainability, and green nature. In this method, conductive silver nanowire patterns on glass substrates were completely transferred to the surface of regenerated cellulose hydrogel by coagulation and regeneration of cellulose solution. The dried silver nanowire pattern regenerated cellulose film exhibited high light transmittance, excellent tensile strength, high sheet resistance, good adhesion stability and excellent bending durability. This regenerated cellulose film swells spontaneously in aqueous solution and can be converted into a silver nanowire pattern on cellulose hydrogel film. This conductive hydrogel membrane can be used as an important component of membranes and coatings in bioelectronics connected to biological systems. Therefore, it is expected to be a suitable microelectrode for the development of next-generation green electronics and high-performance bioelectronics.
Some studies have looked at developing new types of energy generation devices by developing materials through nanoarchitectonics. Feng and Xia, in their recent review, describe the importance of nanoarchitectonics in the development of moistelectric generation devices. [86] The moist-electric generation devices are based on the direct use of fluid potential energy and can directly convert the energy of water or moisture in the environment into electrical energy. The nanoarchitectonics factors that influence the performance of moist-electric generation devices include material development and selection, functional group content, humidity, fluid ion type, fluid ion concentration, fluid velocity control, and carrier transport structure. A variety of new designs are being considered for moist-electric generation devices, including porous material devices, devices based on moisture gradient design, ion concentration difference devices, and ionic liquid devices. All require further experimentation to prove and explore the underlying concepts. The moist-electric generation devices could include wearable, self-powered pressure sensors, breath monitors, motion sensors, LEDs, LCD screens, electronic clocks, and other power sources. As plasma-based nanoarchitectonics, Kansal and Sharma have developed plasma-assisted vertically aligned dual-metal carbon nanotube field-effect transistor simulated devices. [87] The device, which implements vertically aligned semiconducting carbon nanotubes grown in the presence of a plasma sheath as channels, achieves significant performance improvements compared to conventional nanowire fieldeffect transistors. The relationship between plasma parameters during device nanoarchitectonics and device electrical properties was verified. Lower plasma parameter values are essential for higher values of drain current, transconductance, output conductance, and cutoff frequency, and lower values of threshold voltage and channel resistance. On the other hand, higher plasma parameter values could improve the on/off current ratio, initial voltage, and gain. The obtained simulation results help to explain more empirical results, such as the application of the device to digital devices and biosensors.
There are research examples of sensor devices that monitor life and human activity, developed through nanoarchitectonics of materials. For example, in response to various new infectious diseases, remote monitoring of infected persons is of paramount importance to isolate them and prevent the spread of pathogens Figure 14. Membrane-type surface stress sensor coated with copper(I) complexes for selective methanol sensing. Reproduced with permission. [89] Copyright 2021, Chemical Society of Japan.
to health care workers. Pumera and co-workers used an integrated nanoarchitectonics approach to couple a stretchable asymmetric supercapacitor portable power source with a sensor capable of remotely monitoring physical health in real time. [88] Specifically, they developed a method to continuously monitor a person's breathing cycle by wrapping a textile around the abdomen with a FePS 3 @graphene-based strain sensor and a supercapacitor. By integrating a temperature sensor, they also succeeded in recording the body temperature of the entity. These integrated nanoarchitectonics approaches pave the way for the development of innovative wearable e-health monitoring systems based on flexible and stretchable energy storage devices. Nishikawa et al. have developed a nanomechanical sensor device that can sensitively detect methanol in the environment and in gasoline. [89] The membrane-type surface stress sensor used in this research is a nanomechanical sensor device. A methanolsensitive complex molecule is coated on a silicon-based sensor membrane (Figure 14). The membrane-type surface stress sensor converts surface stress derived from deformation (swelling or shrinkage) due to absorption and desorption of a receptor layer coated on a silicon-based membrane into an electrical sig-nal. Target molecule-receptor interactions involving mechanical deformation are detected by this sensor in the medium. Copper(I) complexes with diimines and diphosphine ligands, which are made from inexpensive and abundant metals, are coated as the sensitive film. This nanoarchitecture was demonstrated as a gas sensor capable of detecting methanol contamination in gasoline. Sensitivity when exposed to gasoline vapor containing 1% methanol is a larger than that when the ethanol content in gasoline was 20 times greater than the methanol content. This is useful for detecting illegal methanol mixed with ethanol in gasoline and is also expected to be used to detect toxic methanol in beverages.

Summary and Short Perspectives
Since nanoarchitectonics shares characteristics and interests with conventional concepts such as self-assembly and selforganization, which are commonly used in the field of chemistry, it seems to have applications in the field of chemistry and related biochemical and biological fields ahead of its application. Many studies advocating nanoarchitectonics are related to the www.advancedsciencenews.com www.advphysicsres.com chemistry and bio-chemical fields. For example, in the areas of material creation, [90,91] structural control, [92,93] catalysis, [94,95] sensors, [96,97] basic bio-chemistry, [98,99] biomedical, [100,101] energy, [102,103] and environment. [104,105] However, since nanoarchitectonics is a method of architecting functional structures with a high degree of generality, it should have contributions that are independent of chemistry, physics, and biology. This paper discusses the potential application of nanoarchitectonics to advanced physical research by reviewing several research examples. In addition to those presented here, other research trends in advanced fields are reported, such as the contribution of nanoarchitectonics to neuromorphic devices [106] and the fusion of materials informatics and nanoarchitectonics. [107] Because the nanoarchitectonics concept shares features similar to self-assembly and self-organization in chemistry. this concept is well reviewed in chemistry-related fields. Unlike these previous examples, this article overviewed application possibilities from general viewpoints of physics. It can be said that nanoarchitectonics is a concept that has the potential to contribute to the development of science beyond the boundaries of disciplines.
As we have shown several examples in this paper, structural control through nanoarchitectonics can architect a variety of fields for physical research. New physical properties can be controlled by forming atomic arrangements, molecular designs, polymer syntheses, crystal structures, self-assembled structures, and superstructures. Alternatively, the construction of nanospace structures can elucidate the specific physical properties of molecules trapped in them. Thus, from an overview perspective, nanoarchitectonics has great potential to contribute to advanced physical research. In this review alone, the terms that include nanoarchitectonics are listed including integrated nanoarchitectonics, electrochemical nanoarchitectonics, green nanoarchitectonics, high pressure nanoarchitectonics, photonic function-oriented nanoarchitectonics, sensor nanoarchitectonics, plasma-based nanoarchitectonics, resistance matching materials nanoarchitectonics, and biomimetic lightharvesting nanoarchitectonics. Of course, these examples are only a small fraction of those published and existing. Something missing in this review can be summarized here. Many methods for nanoarchitectonics approaches are possible, but their comparisons are not instantly easy. It can be at least said that method availability is so diverse beyond simple comparison capabilities. In addition to chemical modifications mainly discussed in this paper, many other physical methods such as magnetron sputtering [108,109] or vapor deposition [110][111][112] would work important tools in nanoarchitectonics approaches to obtain functional nanocomposite film structures. Dimensionally restricted materials synthesis such as functional nanowire fabrications [113][114][115][116] have important roles in the nanoarchitectonics strategies. Other types of nanofunctional structures, such as those concerning the electrical properties of heterojunctions of metal-semiconductor materials [117,118] and the physical properties at direct bonding interfaces, [119,120] would also contribute to the nanoarchitectonics approaches. Although this article focuses mainly on optics and electricity properties, the mechanical properties and reliability are also important for nanoscale metals and semiconductors. Especially, size-dependent mechanical properties such as increased elasticity in nanoscale 1D/2D materials would play an increasingly important role in strain engineering of semiconductors for unprecedented microelectronics and optoelectronics. [121][122][123] The contributions of nanoarchitectonics to physics-related fields are diverse, ranging from functional examples to analysis, theory, and concept development.