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Role of Surface States in Photocatalytic Oxygen Evolution with CuWO <sub/>4</sub> Particles
摘要： CuWO4 is a medium bandgap (2.3 eV) n-type semiconductor capable of photoelectrochemical water oxidation under applied electrical bias. Here, we show for the ?rst time that suspended microcrystals CuWO4 evolve oxygen photocatalytically under visible illumination from solutions of 0.05 M AgNO3 (10.8 μmol/hour; AQE of 0.56% at 400 nm) and 0.0002 M FeCl3 (1.5 μmol/hour). No oxygen is detected with 0.002 M [Fe(CN)6]3? as sacri?cial agent. The activity dependence on the redox potential of the acceptors is due to the presence of Cu2+ based electron trap states in CuWO4. According to surface photovoltage spectroscopy and electrochemistry, these states are located on the particle surface, 1.8 eV above the valence band edge of the material. Controlling the chemistry of these states will be key to uses of CuWO4 particles in tandem catalysts for overall water splitting.
关键词： water splitting,CuWO4,sacrificial electron acceptors,photocatalytic oxygen evolution,surface states
更新于2025-09-10 09:29:36
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Introducing Four 1,1-Dicyanomethylene-3-Indanone (IC) End-capped Groups as an Alternative Strategy for the Design of Small Molecular Nonfullerene Acceptors
摘要： Linear A-D-A or A-π-D-π-A architectures are predominant in the design of promising non-fullerene acceptors (NFAs), which promoted the rapid progress of organic solar cells (OSCs). However, utilization of four electron-accepting units (A) to construct four-armed NFAs is rarely reported and the relationship of structure-properties-performance is unclear. In this study, we designed and synthesized a novel acceptor (A401) with (AA)-π-D-π-(AA) configuration, where four 1,1-dicyanomethylene-3-indanone (IC) groups were used as the end-capped segments. When A401 was paired with a classic p-type polymer PBDB-T, a power conversion efficiency (PCE) of 7.54% could be achieved, which was much higher than that of the reported two-armed analogue of DC-IDT2T (3.93%). The improved photovoltaic performance of A401 should be ascribed to the high electron-affinity. Our results indicate introducing more end-capped electron-accepting units is a simple and effective alternative strategy for the design of promising NFAs. Our conceptualized molecular architecture will encourage further research of high-performance multi-armed NFAs.
关键词： photovoltaic performance,electron-affinity,electron-accepting units,organic solar cells,non-fullerene acceptors
更新于2025-09-10 09:29:36