韩国基础科学研究所Kwang Jin Lee同美国罗彻斯特大学郭春雷教授等开展合作研究，发现通过极大抑制三维卤化铅钙钛矿的复合率能够增强光电探测器性能。这一研究成果于2023年2月16日发表在国际顶尖学术期刊《自然—光子学》上

研究小组发现当将三维LHP多晶薄膜放置在双曲超材料上时，其复合率显著降低。通过动量分辨成像，研究人员揭示了这些LHP薄膜具有主导的面内跃迁偶极矩，这反过来又导致复合率的降低。该研究小组还观察到，当将MAPbI₃ LHP薄膜置于等离子体反射镜和双曲超材料上时，其复合率分别降低了约50%和30%。

此外，课题组人员发现(Cs_0.06FA_0.79MA_0.15)Pb(I_0.85Br_0.15)₃的复合率下降了10倍，并基于激子捕获动力学讨论了这种复合过程中大幅降低的原因。通过控制LHPs的复合率，研究小组证明了基于LHPs的光电探测器的光响应率增加了250%。由此产生的物理见解将为提高基于LHP的光电和光子器件的效率提供新的手段。

据了解，延长卤化铅钙钛矿(LHP)中载流子的寿命可以实现高效能量收集和光探测应用的新方案。然而，在不进行化学处理的情况下抑制LHP中的复合过程仍然是一个开放的挑战。

附：英文原文

Title: Gigantic suppression of recombination rate in 3D lead-halide perovskites for enhanced photodetector performance

Author: Lee, Kwang Jin, Wei, Ran, Wang, Ye, Zhang, Jihua, Kong, Wenchi, Chamoli, Sandeep Kumar, Huang, Tao, Yu, Weili, ElKabbash, Mohamed, Guo, Chunlei

Issue&Volume: 2023-02-16

Abstract: Prolonging the carrier lifetime in lead-halide perovskite (LHP) can enable novel schemes for highly efficient energy-harvesting and photodetection applications. However, suppressing the recombination processes in LHP without chemical treatments remains an open challenge. Here we show that the recombination rate of three-dimensional LHP polycrystalline thin films can decrease significantly when placed on hyperbolic metamaterials. Through momentum-resolved imaging, we reveal that these LHP films possess a dominant in-plane transition dipole, which in turn is responsible for the decrease in the recombination rate. We observe a decrease in the recombination rate of a MAPbI₃ LHP thin film by ~50% and 30% when placed on a plasmonic mirror and a hyperbolic metamaterial, respectively. Furthermore, we discover a tenfold decrease in the recombination rate of (Cs_0.06FA_0.79MA_0.15)Pb(I_0.85Br_0.15)₃, and the origin of this giant reduction in the recombination process is discussed based on exciton-trapping dynamics. By controlling the recombination rate of LHPs, we demonstrate a 250% increase in photoresponsivity of LHP-based photodetectors. The resulting physical insights will provide novel means to enhance the efficiency of LHP-based optoelectronic and photonic devices.

DOI: 10.1038/s41566-022-01151-3

Source: https://www.nature.com/articles/s41566-022-01151-3