Exploring novel ligands with strong electron delocalization for high-performance blue CsPbBr perovskite nanoplatelets

• Published in: Journal of materials chemistry. C, Materials for optical and electronic devices Materials for optical and electronic devices, 2022-07, Vol.1 (26), p.9834-984
• Main Authors: Wen, Zhuoqi, Cui, Zhongjie, He, Haiyang, Yang, Dan, Mei, Shiliang, Yang, Bobo, Xiong, Zhiyong, Song, Shanliang, Bao, Rui, Zhang, Wanlu, Xing, Guichuan, Xie, Fengxian, Guo, Ruiqian
• Format: Article
• ISSN: 2050-7526; 2050-7534
• DOI: 10.1039/d2tc01687g

Colloidal CsPbBr 3 perovskite nanoplatelets (NPLs) with readily controllable thickness are considered promising blue-emitting materials. However, the relatively low photoluminescence quantum yield (PLQY) and poor stability hinder their further applications. Herein, a class of novel surface ligands, such as 2-butynoic acid (BtA), phenylpropiolic acid (PA) and 2-pentynoic acid (PtA), are proposed for conveniently preparing high-performance blue-emitting NPLs. Benefiting from the strong electron delocalization effect of alkynyl, the protonated amine species (RNH 3 + ) and R-C&z.tbd;C-COO − prefer to coordinate with the perovskite, which can not only enhance the PLQY of NPLs from ∼15% to ∼100%, but also promote their endurability to high temperatures and strong UV irradiation. To our knowledge, this is the first report on the post-treatment of perovskites with electron delocalized ligands containing alkynyl and the effect of electron delocalization of Lewis bases on high-performance NPLs is systematically investigated from the perspective of molecular structure, which will be helpful to develop novel short-chain and conjugated ligands for perovskite electroluminescence devices. Lewis bases with strong electron delocalization can affect the chemical equilibrium of the system. Therefore, the R-NH 3 + and R-C≡C-COO − prefer to coordinate with NPLs, passivating the surface defects and improving the stability of crystals.