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

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 mu s to 62.25 mu s. 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.