Highly efficient orange luminescence in Sn2+-doped Cs2AgInCl6 double perovskite with a large Stokes shift

Abstract

Halide double perovskites (HDPs) show great potential as lead-free alternatives for various optoelectronic devices. However, the device performance of HDPs remains significantly below optimal levels, limiting their applications. In this work, Cs₂AgInCl₆ emitting orange light was synthesized using the anti-solvent method, and the optical performance was greatly improved by doping Sn²⁺ to substitute In³⁺ due to the enhanced self-trapped exciton (STE) emission. The intensity of photoluminescence (PL) was greatly enhanced, with the Stokes shift of Cs₂AgInCl₆:xSn²⁺ being approximately 360 nm in the visible light region. The full width at half maximum (FWHM) was 270 nm. Cs₂AgInCl₆:0.13Sn²⁺ exhibited the highest photoluminescence quantum yield (PLQY) of 29%, which was nearly 15 times higher than that of Cs₂AgInCl₆. The lifetime was extended from 3.36 μs to 62.25 μs. Besides, the doped double perovskite exhibited better storage performance than Cs₂AgInCl₆. The WLED fabricated with Cs₂AgInCl₆:0.13Sn²⁺ showed an appropriate CCT of 4210 K and a high CRI of 97. These results provide further insights into the Sn²⁺-doped Cs₂AgInCl₆ with a large Stokes shift, improving its optical properties and applications, such as WLEDs.