清华大学林元华团队报道了二维卤化物钙钛矿的高熵设计。相关研究成果于2024年7月9日发表在《美国化学会志》。

混合卤化物钙钛矿由于其可调带隙、长载流子扩散长度和溶液可加工性，是一系列功能材料（如光电器件和光伏器件）的良好候选者。然而，长期以来，湿气/空气中的不稳定性、铅的毒性以及严格的反应设置或复杂的后处理一直是实际应用的瓶颈。

该文中，研究人员提出了在典型的（CHA）₂PbBr₄二维（2D）杂化钙钛矿中的A位、B位和X位同时进行的构型熵设计。研究结果表明，高熵效应有利于混合钙钛矿相的稳定，并促进了简单的结晶过程，而无需精确控制冷却速率来制备规则晶体。

此外，高熵2D钙钛矿晶体表现出可调谐的能带隙、宽带发射和长载流子寿命。同时，高熵组分在去离子水中18小时几乎保持初始晶体结构，而原始（CHA）₂PbBr₄晶体大部分分解，表明湿度稳定性明显提高。

该项工作提供了一种在温和条件下合成湿度稳定的混合钙钛矿的简单方法，加速了光电子和发光器件的相关制备，并促进了卤化物钙钛矿的最终商业化。

附：英文原文

Title: High-Entropy Design for 2D Halide Perovskite

Author: Yan Song, Shun Lan, Bingbing Yang, Yunpeng Zheng, Zhifang Zhou, Ce-Wen Nan, Yuan-Hua Lin

Issue&Volume: July 9, 2024

Abstract: Hybrid halide perovskites are good candidates for a range of functional materials such as optical electronic and photovoltaic devices due to their tunable band gaps, long carrier diffusion lengths, and solution processability. However, the instability in moisture/air, the toxicity of lead, and rigorous reaction setup or complex postprocessing have long been the bottlenecks for practical application. Herein, we present a simultaneous configurational entropy design at A-sites, B-sites, and X-sites in the typical (CHA)2PbBr4 two-dimensional (2D) hybrid perovskite. Our results demonstrate that the high-entropy effect favors the stabilization of the hybrid perovskite phase and facilitates a simple crystallization process without precise control of the cooling rate to prepare regular crystals. Moreover, high-entropy 2D perovskite crystals exhibit tunable energy band gaps, broadband emission, and a long carrier lifetime. Meanwhile, the high-entropy composition almost maintains the initial crystal structure in deionized water for 18 h while the original (CHA)2PbBr4 crystal mostly decomposes, suggesting obviously improved humidity stability. This work offers a facile approach to synthesize humidity-stable hybrid perovskites under mild conditions, accelerating relevant preparation of optoelectronics and light-emitting devices and facilitating the ultimate commercialization of halide perovskite.

DOI: 10.1021/jacs.4c01882

Source: https://pubs.acs.org/doi/abs/10.1021/jacs.4c01882