Xuan Zhu, Lin Zhou, Xiao-Yun Huang, Yan-Ling Luo, Xin Deng, Xin Yan, Yan-Juan Wang, Yan Qin*, Yuan-Yuan Tang*

Cite this article: Chin. J. Struct. Chem., 2024, 43: 100272. DOI: 10.1016/j.cjsc.2024.100272

Publication date: June 15, 2024

Keywords: Lead-free perovskite; Photoluminescence; Two-dimensional perovskite; Lead-free perovskite

ABSTRACT

Two-dimensional (2D) lead halide perovskites have attracted tremendous attention due to their outstanding physical properties. However, the presence of toxic lead is a major problem for large-scale applications. Here, we report the synthesis, phase transition, dielectric and photoluminescence (PL) properties of a lead-free 2D Ge-based perovskite (BIM)₂GeI₄ (BIM = benzimidazolium) which experiences a phase transition at 405 K accompanied by an order-disorder change of organic spacer. Moreover, the step-like dielectric transition near the phase transition temperature makes it suitable for dielectric switching. Meanwhile, (BIM)₂GeI₄ has a direct bandgap of 2.23 eV and broadband emission from 550 to 1000 nm, implying its unique optical property for potential near-infrared lighting and displaying. This work provides a fresh example for the development of lead-free 2D Ge-based perovskite with potential applications in the fields of optoelectronics and high temperature dielectric switching.