Triggs Christopher T, Wu Chun-Sheng Jack, He Yarong, Bernat Eliana, Mihalyi-Koch Willa, Forlano Kristel M, Guzei Ilia A, Cortecchia Daniele, Petrozza Annamaria, Jin Song
Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53703, United States.
Center for Nanoscience and Technology, Istituto Italiano di Tecnologia, via Rubattino 81, Milano 20134, Italy.
J Am Chem Soc. 2025 Sep 24;147(38):34706-34720. doi: 10.1021/jacs.5c09938. Epub 2025 Sep 15.
Two-dimensional (2D) tin halide perovskites are highly tunable and low-toxicity semiconductors, promising for next-generation optoelectronics. However, achieving air stability and excellent photophysical properties simultaneously necessitates deliberate structure tuning using organic spacer cations and A-site cations. Here, we report a series of new quasi-2D Ruddlesden-Popper tin halide perovskites using a fluorinated aromatic spacer cation, 4-fluorophenethylammonium (4FPEA), and systematically investigate the impacts of layer thickness, spacer cation, and A-site cation on the crystal structures and optical properties of (4FPEA)(A)SnI. These 4FPEA-based 2D tin perovskites, further tuned by the A-cations, exhibit uniquely undistorted 180° out-of-plane Sn-I-Sn bond angles and low octahedral distortions compared to other quasi-2D perovskites and demonstrate prolonged air stability, excellent photophysics, and amplified spontaneous emission and lasing in exfoliated microflakes. A comprehensive survey of reported = 2 lead and tin iodide perovskites reveals that all structures can be classified into three types (tilted, balanced, and buckled) based on the structural distortion parameters of their perovskite cages. Notably, (4FPEA)(A)SnI are among the handful of "balanced" = 2 perovskites with minimal distortion and excellent optoelectronic performance. The structural insights and cage-balancing approach revealed herein motivate the deliberate design of quasi-2D perovskites through the synergy of the spacer and cage cations, further paving the way for high-performance optoelectronic applications of stable tin halide perovskites.
二维（2D）卤化锡钙钛矿是具有高度可调性和低毒性的半导体，在下一代光电子学领域颇具前景。然而，要同时实现空气稳定性和优异的光物理性质，就需要使用有机间隔阳离子和A位阳离子进行精心的结构调整。在此，我们报道了一系列使用氟化芳香族间隔阳离子4-氟苯乙铵（4FPEA）的新型准二维Ruddlesden-Popper卤化锡钙钛矿，并系统研究了层厚度、间隔阳离子和A位阳离子对(4FPEA)(A)SnI晶体结构和光学性质的影响。这些基于4FPEA的二维锡钙钛矿通过A阳离子进一步调整，与其他准二维钙钛矿相比，呈现出独特的未扭曲的180°面外Sn-I-Sn键角和低八面体畸变，并展现出延长的空气稳定性、优异的光物理性质，以及在剥离的微片中放大的自发辐射和激光发射。对已报道的n = 2的碘化铅和碘化锡钙钛矿的全面调查表明，根据其钙钛矿笼的结构畸变参数，所有结构可分为三种类型（倾斜、平衡和弯曲）。值得注意的是，(4FPEA)(A)SnI是少数具有最小畸变和优异光电性能的“平衡”n = 2钙钛矿之一。本文揭示的结构见解和笼平衡方法，通过间隔阳离子和笼阳离子的协同作用，激发了对准二维钙钛矿的精心设计，进一步为稳定卤化锡钙钛矿的高性能光电子应用铺平了道路。
