Yahui Li,Shuo Li,Yun Wu,Juan Zhang,YiYi Yang,Hui Mao,Yu Zhang,Xi-ming Song
Illuminating the charge transport at photoanode-electrolyte interface is pivotal for optimizing photoelectrochemical (PEC) water oxidation performance of BiVO 4 . Our study demonstrates a preferentially photogenerated electrons trapping process at BiVO 4 surface, followed by the formation of surface-bound excitons. A facile LSV treatment method is described, which remarkably passivate the surface electron trapping states by the formation surface oxygen vacancies. The surface oxygen vacancies could “free” the photogenerated holes from the surface-bound excitons. As a result, more photogenerated holes are available on BiVO 4 surface and the PEC performance is enhanced.
Rong Chen,Fang Lin,Wenqing Wei,Mei Liu,Wanxu Zhang,Yongzhuo Zheng,Juan Wang,Fengwan Guo
The field of metal halide engineering has made considerable progress, yet additional studies are needed to completely grasp the intriguing principles that govern their luminescence. In this work, we report a novel zero-dimensional (0D) organic-inorganic metal halide hybrid (OIMH) (C 3 H 12 N 2 ) 2 InCl 7 (C 3 H 12 N 2 = 1,3-propane diamine cation) and reveal its interesting luminescent properties through experimental research and theoretical calculations. The photoluminescence (PL) of (C 3 H 12 N 2 ) 2 InCl 7 is a synergistic combination of intrinsic self-trapped exciton (STE) emission and defect-bound exciton (DBE) emission. Doping with Sb 3+ induces several changes in (C 3 H 12 N 2 ) 2 InCl 7 , including defect passivation, a reduction in the band gap, and structural shrinkage. These modifications result in a transition of PL centers to external STE emission, with the photoluminescence quantum yield (PLQY) increasing from 4.44 % to 68.70 %. Our work proposes, for the first time, the synergistic emission of STE and DBE and reveals the effect of metal ion doping, providing new insights into the mechanisms of materials exhibiting multifunctional exciton emission.
Shuo Wang,Shuhan Zhang,Xin Li,Dan Huang,William W. Yu,Liang Wang
Near-infrared (NIR) emission underpins biomedical imaging, night vision, and optical communication. Yb 3+ -doped CsPbCl 3 have demonstrated ultrahigh photoluminescence quantum yields via quantum cutting, primarily enabled by a singular defect-assisted energy transfer pathway arising from the substitution of Pb 2+ by Yb 3+ . However, whether additional pathways exist to facilitate visible (VIS)-to-NIR conversion, thereby further enhancing the performance of NIR-emissive devices, remains an open and compelling question. Here, strategic engineering of localized bound excitons (BEs) is proposed in the thermally evaporated CsPbCl 3 :Yb system. Assisted BEs significantly promote energy transfer from CsPbCl 3 matrix to Yb dopants, unveiling a previously unknown excitonic energy transfer channel. Atomic-scale characterization combined with first-principles calculations uncovers a BE-driven excitonic transfer mechanism, specifically implicating Cs-vacancy-induced defects in mediating exciton behavior. These insights lead to the fabrication of high-performance NIR-LEDs with an 8.9% external quantum efficiency and 410 mW·Sr −1 ·m −2 radiance, marking a breakthrough in thermally evaporated NIR (>950 nm) light-emitting diodes.
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