Tunable Dual Emission in Bi3+/Te4+-Doped Cs(2)HfCl(6)DoublePerovskites for White Light-Emitting Diode Applications br

Multicolor-emission-based single-phase white light derived from differentluminescence centers is an effective way to manipulate the optical properties of halideperovskites. In this work, we developed a codoping strategy to incorporate Bi3+and Te4+emission centers into all-inorganic lead-free Cs2HfCl6perovskite by a hydrothermal method.The as-prepared Bi3+/Te4+-doped Cs2HfCl6microcrystals show bright blue (Bi3+), yellow(Te4+), and warm-white emissions (Bi3+/Te4+), respectively. The broad efficient dual emissionin Bi3+/Te4+co-doped Cs2HfCl6is assigned to the typical3P1 -> 1S0transition emission fromBi3+originating from [BiHf+VCl] and self-trapped excitons (STEs) from Te4+. Moreover, theconcentration-optimized Cs2HfCl6:Te4+shows excellent antiwater stability and high photo-luminescence quantum yield (PLQY) of similar to 70%. Meanwhile, a white light-emitting diode(WLED) fabricated using Bi3+/Te4+co-doped Cs2HfCl6is close to warm white with a colorrendering index (CRI) of 75.4, CIE color coordinate of (0.370, 0.393), and a correlated colortemperature (CCT) of 4380 K. These results suggest that Bi3+/Te4+co-doped all-inorganiclead-free Cs2HfCl6is a potential single-phase white light-emitting phosphor candidate for solid-state lightings.