日本冲绳科学技术研究所研究生大学Yabing Qi团队开发了非对称有机二胺基Dion-Jacobson钙钛矿光谱稳定蓝光发射二极管。相关研究成果发表在2021年11月18日出版的《美国化学会杂志》。

在蓝色钙钛矿发光二极管（PELEDs）中，光谱不稳定性问题是一个挑战。Dion–Jacobson（DJ）相钙钛矿是实现高质量蓝色PELEDs的有希望的替代物。然而，目前对DJ相钙钛矿的研究主要集中在对称二价阳离子上，蓝色钙钛矿的相应效率仍低于绿色和红色钙钛矿。

该文中，研究人员报道了一种新型的DJ相CsPb(Br/Cl)3钙钛矿，通过在钙钛矿中引入不对称分子结构作为有机间隔阳离子。不对称阳离子上的伯铵和叔铵基团与形成DJ相结构的卤化铅八面体桥接。由于抑制了卤化物的偏析，钙钛矿薄膜表现出稳定的光致发光光谱。同时，由于电荷陷阱的限制效应和钝化作用，电荷的辐射复合效率显著提高。最后，在外加偏压下，在稳定光谱发射的蓝色PELEDs中实现了2.65%的外部量子效率。这是第一份关于PELEDs中使用的不对称阳离子的报告，它为PELEDs中的卤化物分离问题提供了一个简单的解决方案。

附：英文原文

Title: Spectral Stable Blue-Light-Emitting Diodes via Asymmetric Organic Diamine Based Dion–Jacobson Perovskites

Author: Yuqiang Liu, Luis K. Ono, Guoqing Tong, Tongle Bu, Hui Zhang, Chenfeng Ding, Wei Zhang, Yabing Qi

Issue&Volume: November 18, 2021

Abstract: The spectral instability issue is a challenge in blue perovskite light-emitting diodes (PeLEDs). Dion–Jacobson (DJ) phase perovskites are promising alternatives to achieve high-quality blue PeLEDs. However, the current exploration of DJ phase perovskites is focused on symmetric divalent cations, and the corresponding efficiency of blue PeLEDs is still inferior to that of green and red ones. In this work, we report a new type of DJ phase CsPb(Br/Cl)3 perovskite via introduction of an asymmetric molecular configuration as the organic spacer cation in perovskites. The primary and tertiary ammonium groups on the asymmetric cations bridge with the lead halide octahedra forming the DJ phase structures. Stable photoluminescence spectra were demonstrated in perovskite films owing to the suppressed halide segregation. Meanwhile, the radiative recombination efficiency of charges is improved significantly as a result of the confinement effects and passivation of charge traps. Finally, we achieved an external quantum efficiency of 2.65% in blue PeLEDs with stable spectra emission under applied bias voltages. To our best knowledge, this is the first report of asymmetric cations used in PeLEDs, which provides a facile solution to the halide segregation issue in PeLEDs.

DOI: 10.1021/jacs.1c07757

Source: https://pubs.acs.org/doi/10.1021/jacs.1c07757