材料科学
载流子
光致发光
载流子寿命
半导体
各向异性
无辐射复合
单晶
扩散
凝聚态物理
Crystal(编程语言)
重组
结晶学
光电子学
光学
硅
化学
物理
半导体材料
基因
程序设计语言
热力学
生物化学
计算机科学
作者
Jie Zhang,Kaiyu Wang,Qing Yao,Ye Yuan,Jianxu Ding,Weiwei Zhang,Haiqing Sun,Chenyu Shang,Changqian Li,Tianliang Zhou,Shuping Pang
标识
DOI:10.1021/acsami.1c07056
摘要
MAPbI3, one of the archetypical metal halide perovskites, is an exciting semiconductor for a variety of optoelectronic applications. The photoexcited charge-carrier diffusion and recombination are important metrics in optoelectronic devices. Defects in grain interiors and boundaries of MAPbI3 films cause significant nonradiative recombination energy losses. Besides defect impact, carrier diffusion and recombination anisotropy introduced by structural and electronic discrepancies related to the crystal orientation are vital topics. Here, large-sized MAPbI3 single crystals (SCs) were grown, with the (110), (112), (100), and (001) crystal planes simultaneously exposed through the adjusting ratios of PbI2 to methylammonium iodide (MAI). Such MAPbI3 SCs exhibit a weak n-type semiconductor character, and the Fermi levels of these planes were slightly different, causing a homophylic p–n junction at crystal ledges. Utilizing MAPbI3 SCs, the photoexcited carrier diffusion and recombination within the crystal planes and around the crystal ledges were investigated through time-resolved fluorescence microscope. It is revealed that both the (110) and (001) planes were facilitated to be exposed with more MAI in the growth solutions, and the photoluminescence (PL) of these planes manifesting a red-shift, longer carrier lifetime, and diffusion length compared with the (100) and (112) planes. A longer carrier diffusion length promoted photorecycling. However, excessive MAI-assisted grown MAPbI3 SCs could increase the radiative recombination. In addition, it revealed that the carrier excited within the (001) and (112) planes was inclined to diffuse toward each other and was favorable to be extracted out of the grain boundaries or crystal ledges.
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