Electronically modulated d-band centers of MOF-derived carbon-supported Ru/HfO_(2) for oxygen reduction and aqueous/flexible zinc-air batteries

The construction of oxide/metal composite catalysts is a competent means of exploiting the electronic interactions between oxide/metal to enhance catalytic activity.In this work,we construct a novel heterogeneous composite(Ru/HfO_(2)-NC)with Ru/HfO2nanoparticles nested in nitrogen-doped porous carbon via a zeolitic imidazole frameworks-assisted(ZIF)co-precipitation and calcination approach.In particular,ZIF guides an in-situ construction of nested configuration and confines the scattered nanoparticles.Strikingly,Ru/HfO_(2)-NC exhibits unusual ORR activity,superb durability,and methanol tolerance in0.1 M KOH solution with high half-wave potential(E1/2)of 0.83 V and follows a near-4e-reaction pathway.Additionally,the ZAB assembled with cathodic Ru/HfO_(2)-NC outputs a power density of 157.3 m W cm^(-2),a specific capacity of 775 mA h g-1Zn,and a prolonged lifespan of 258 h at 5 mA cm^(-2).Meanwhile,the catalyst has demonstrated potential applicability in flexible ZAB.As suggested by experimental results and density functional theory(DFT)analysis,the remarkable property possibly originated from the optimization of the adsorption and desorption of reactive intermediates caused by the reconfiguration of the electronic structure between Ru and HfO_(2).

A highly efficient open-shell singlet luminescent diradical with strong magnetoluminescence properties

Developing open-shell singlet(OS)diradicals with high luminescent properties and exceptional single-molecule magnetoluminescence(ML)performance is extremely challenging.Herein,we propose a concept to enhance luminescent efficiency by adjusting the donor conjugation of OS diradicals,thereby achieving a highly luminescent diradical,DR1,with outstanding stability and making it a viable option for use in the emitting layer of organic light-emitting diodes(OLEDs).More importantly,the 0.5wt%-DR1 doped film demonstrates significant single-molecule magnetoluminescence(ML)properties.A giant ML value of 210%is achieved at a magnetic field of 7T,showing the great potential of DR1 in magneto-optoelectronic devices.

Quantum dots for optoelectronics

1 Introduction:Development of Quantum Dot Materials Four decades ago,Ekimov and Efros embarked on their research into semiconductor-doped glasses and the formulation of theories to understand their characteristics.^(1,2)Meanwhile,Louis Brus was delving into semiconductor particles within liquid colloids.^(3)These two distinct research endeavors,as well as the efforts of synthetic chemists represented by Bawendi et al.,^(4,5)eventually led to the development of fascinating quantum dot(QD)materials.

Microcavity top-emission perovskite light-emitting diodes

Light-emitting diodes(LEDs)based on perovskites show great potential in lighting and display applications.However,although perovskite films with high photoluminescence quantum efficiencies are commonly achieved,the efficiencies of perovskite LEDs are largely limited by the low light out-coupling efficiency.Here,we show that high-efficiency perovskite LEDs with a high external quantum efficiency of 20.2% and an ultrahigh radiant exitance up to 114.9mWcm^(−2) can be achieved by employing the microcavity effect to enhance light extraction.The enhanced microcavity effect and light outcoupling efficiency are confirmed by the study of angle-dependent emission profiles.Our results show that both the optical and electrical properties of the device need to be optimized to achieve high-performance perovskite LEDs.

The Key Role of Subtle Substitution for a High-Performance Ester-Modified Oligothiophene-Based Polymer Used in Photovoltaic Cells

In organic solar cells (OSCs), developing high-performing easily synthesized photoactive materials is essential for pursuing cost- effective balance. Herein, we have designed and synthesized a pair of wide-band-gap polymers (PBDE4T-0F and PBDE4T-2F), using the low synthesis cost dicarboxylic ester-substituted quaterthiophene as the building block. Despite the minor change of molecular structure for polymer PBDE4T-xF, the fluorine substituent in polymer PBDE4T-2F greatly enhances its interchain aggregation. The higher aggregation tendency of ester-modified polymer in solution is beneficial for reducing both the aggregate size and π-π stacking distance of blend film, which contribute to the highly efficient exciton dissociation and symmetric charge transport. An impressive power-conversion efficiency (PCE) of 16.1% is achieved for the PBDE4T-2F:BTP-eC9-based device, while its counterpart only delivers a PCE of 5.8% with distinctly lower short-circuit current density (J_(sc)) and fill factor. Notably, the aggregation effect of donor polymer has also been found to be associated with the energy level shifts, and thus the variation of charge transfer energy and voltage losses for blend system. The results suggest that simultaneously reduced voltage loss and increased J_(sc) can be expected by further finely tuning the aggregation behavior of the ester-modified oligothiophene-based donor polymer.