Pan Ruiheng, Liu Yutong, Xie Jifan, Wang Rongyu, Liu Xin, Zheng Jiayu, Tang Xiantong, Wang Yongjie, Wang Zhen, Zhou Xianju, Dang Yangyang
School of Science, Chongqing University of Posts and Telecommunications, Chongqing 400065, China.
College of Optoelectronic Engineering, Chongqing University of Posts and Telecommunications, Chongqing 400065, China.
Inorg Chem. 2024 Nov 11;63(45):21617-21626. doi: 10.1021/acs.inorgchem.4c03998. Epub 2024 Oct 31.
Chiral lead halide perovskites (chiral LHPs) have emerged as one of the best candidates for opto-spintronics due to their large spin-orbit coupling (SOC) and unique chirality-induced spin selectivity (CISS) even in the absence of a magnetic field. Here, we report the impact of halide composition on circular dichroism (CD) and magneto-photoluminescence (PL) effects of chiral 2D LHPs (/-MBA)PbBrI (MBA = CHCH(CH)NH). By tuning the mixing ratio of Br/I halide anions, we find that (/-MBA)PbBrI thin films exhibit tunable and wide wavelength range CD signals. Simultaneously, the main CD signals near the exciton absorption band gradually blue shift until they disappear. Moreover, the halogen-dependent negative magneto-PL effects of (/-MBA)PbBrI thin films excited by left/right circularly polarized light can be detected at room temperature. We demonstrated that the halide composition can effectively modulate exciton splitting and chirality transfer in (/-MBA)PbBrI owing to the chirality-induced SOC and crystalline structure transition, which lead to the adjustable CD signals. The interplay of Rashba-type band spin splitting and spin mixing among bright triplet exciton states is responsible for the halogen-dependent magneto-PL effect of chiral 2D LHPs. This study enables chiral 2D LHPs with CISS to be a new class of promising opto-spintronics materials for exploring high-performance spin-light-emitting diodes by halide engineering.
手性卤化铅钙钛矿（手性LHP）由于其大的自旋轨道耦合（SOC）和即使在没有磁场的情况下也具有独特的手性诱导自旋选择性（CISS），已成为光自旋电子学的最佳候选材料之一。在此，我们报告了卤化物组成对手性二维LHP（/-MBA）PbBrI（MBA = CHCH(CH)NH）的圆二色性（CD）和磁光致发光（PL）效应的影响。通过调节Br/I卤化物阴离子的混合比例，我们发现（/-MBA）PbBrI薄膜表现出可调谐且波长范围宽的CD信号。同时，激子吸收带附近的主要CD信号逐渐蓝移直至消失。此外，在室温下可以检测到由左旋/右旋圆偏振光激发的（/-MBA）PbBrI薄膜的卤素依赖性负磁光致发光效应。我们证明，由于手性诱导的SOC和晶体结构转变，卤化物组成可以有效地调节（/-MBA）PbBrI中的激子分裂和手性转移，这导致了可调谐的CD信号。Rashba型能带自旋分裂与明亮三重态激子态之间的自旋混合相互作用是手性二维LHP的卤素依赖性磁光致发光效应的原因。这项研究使具有CISS的手性二维LHP成为一类新型的有前途的光自旋电子学材料，可通过卤化物工程探索高性能自旋发光二极管。
