Broadband and Warm White Emission in Cs2In1-xCl5·H2O:xAg+ Phosphors Enabled by H3PO2 - Mediated Stabilization

The quest for lead-free materials capable of emitting white-light has been a focal point in the realm of luminescent materials due to their potential applications in lighting and display technologies. This study presents a novel approach to achieving broadband white-light emission through the doping of Ag+ in zero-dimensional (0D) lead-free perovskite Cs2InCl5·H2O (CICH), and the strategic addition of H3PO2 (HPA) to facilitate the substitution of Ag+ for In3+. The PL spectra revealed that the emission intensity and the corresponding lifetime of the Ag+-doped CICH samples increased with Ag+ concentration, reaching a maximum at 7% Ag+ doping. This enhancement is attributed to the suppression of non-radiative recombination and the enhancement of self-trapped excitons (STEs) emission, which is a direct result of the structural deformation induced by Ag+ substitution for In3+. The large Stokes shift of 255 nm and the long luminescence lifetime of 20.56 μs observed in the optimized sample S7-CICH:Ag+ underscore the high quality of the STEs emission. The thermal stability of the CICH:Ag+ was exceptional, with a decomposition temperature exceeding 600 °C, indicating their resilience in high-temperature environments. The significance of this research lies in the development of a new class of lead-free luminescent materials that combine high efficiency, broad emission, and thermal stability.