Enhanced Blue Emission in Rb<sub>2</sub>HfCl<sub>6</sub> Double Perovskite via Bi<sup>3+</sup> Doping and Cs<sup>+</sup> Alloying
Haoyue Wan, Fengyan Jia, Filip Dinic, Muhammad Imran, Benjamin Rehl, Yanjiang Liu, Watcharaphol Paritmongkol, Pan Xia, Ya‐Kun Wang, Yuan Liu, Sasa Wang, Quan Lyu, Giovanni Cotella, Peter Chun, Oleksandr Voznyy, Sjoerd Hoogland, Edward H. Sargent
Abstract
Lead-free double perovskites offer non-toxic properties and strong emission via alloying and doping. Herein, we report the synthesis of Bi-doped pure Rb 2 HfCl 6 and Cs-alloyed RbCsHfCl 6 microcrystals. The pure Rb 2 HfCl 6 microcrystals are nearly non-emissive while alloying with Cs and Bi doping lead to strong deep blue emission at 466 nm with an increase in photoluminescence quantum yield from ∼0 to 66%. Density functional theory studies attest to the improved phase stability due to Cs-alloying and link photoluminescence to Bi 3+ dopant-induced localized states.