Precursor Tailoring Enables Alkylammonium Tin Halide Perovskite Phosphors for Solid‐State Lighting
Ziliang Li, Zhengtao Deng, Andrew Johnston, Jingwei Luo, Haijie Chen, Yitong Dong, Randy P. Sabatini, Edward H. Sargent
Abstract
Abstract Broadband emission with a large Stokes shift is of interest for applications in solid‐state lighting. Such emission is often achieved with self‐trapped excitons; however, in reduced‐dimensional perovskites, high‐performance self‐trapped emission has, until now, been widely observed only in lead‐based materials. Here, the synthesis in an air ambient of reduced‐dimensional Sn‐based perovskite phosphors R 2 + x SnI 4 + x [R = octylammonium (OTA), hexylammonium (HA) or butylammonium (BA)] is reported, an advance achieved by tailoring the synthesis of the Ruddlesden‐Popper 2D perovskites R 2 SnI 4 . The lead‐free R 2 + x SnI 4 + x phosphors have broadband self‐trapped emission with over 80% photoluminescence quantum yield (PLQY) and more than a 150 nm Stokes shift. White‐light‐emitting diodes (WLEDs) based on OTA 2 + x SnI 4 + x phosphors exhibit warm‐white emission (correlated color temperature = 2654K) suited to home lighting, and a CRI of 92, among the best for Pb‐free perovskite WLEDs reported to date.