Haoyue Wan1,Fengyan Jia1,Filip Dinic1,Benjamin Rehl1,Muhammad Imran1,Yanjiang Liu1,Watcharaphol Paritmongkol1,Pan Xia1,Yuan Liu1,Sasa Wang1,Yakun Wang1,Oleksandr Voznyy1,Sjoerd Hoogland1,Edward Sargent1
University of Toronto1
Haoyue Wan1,Fengyan Jia1,Filip Dinic1,Benjamin Rehl1,Muhammad Imran1,Yanjiang Liu1,Watcharaphol Paritmongkol1,Pan Xia1,Yuan Liu1,Sasa Wang1,Yakun Wang1,Oleksandr Voznyy1,Sjoerd Hoogland1,Edward Sargent1
University of Toronto1
<b>Lead-free double perovskites offer non-toxic properties and strong emission via alloying and doping. Herein we report the synthesis of pure Rb<sub>2</sub>HfCl<sub>6</sub> microcrystals as well as Cs-alloyed and Bi-doped RbCsHfCl<sub>6</sub> microcrystals. While pure Rb<sub>2</sub>HfCl<sub>6</sub> is almost non-emissive, alloying with Cs and </b><b>Bi</b><b> doping led to strong deep blue emission at 466 nm with the photoluminescence quantum yield increase from ~0% to 66%. Density functional theory studies attest to improved phase stability upon Cs alloying and link photoluminescence to Bi<sup>3+</sup> dopant-induced localized states.</b>