Advanced Functional Materials

A Pt(II)-based doping-free phosphorescent organic light-emitting diode with an external quantum efficiency of 20.3% and power efficiency of 63.0 lm W⁻¹ is demonstrated. The device efficiency roll-off at high current densities is assessed quantitatively by deriving the triplet-triplet annihilation and triplet-polaron quenching rate constants. The contributions from loss of charge balance and field-induced exciton dissociation are essentially excluded in this device.

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).