Efficient and stable silver-europium codoped lead-free double perovskite nanocrystals for warm-white emission

Owing to their unique optical properties and nontoxicity, lead-free halide double perovskite nanocrystals are of interest for widespread applications. Herein, the colloid synthesis and photoluminescence property of Ag + -Eu 3+ codoped Cs 2 NaInCl 6 nanocrystals were investigated. The perovskite nanocrystals exhibit a broad warm-white photoluminescence with correlated color temperature (CCT) of 3447 K and color rendering index (CRI) of 90.2, and the means of codoping would improve its optical performance. A fast energy transfer and a long-lived self-trapped excitons state are unveiled by the femtosecond transient absorption spectra. The fast energy transfer from the self-trapped excitons of host nanocrystals to the Eu 3+ ions is helpful to achieve a broad photoluminescence, and the quantum yield of Cs 2 NaInCl 6 :0.05Ag + -Eu 3+ nanocrystals can be enhanced to 69.5%. There is a large exciton binding energy and strong electron-phonon interaction in the codoped perovskite nanocrystals. The efficient and excellent air-stable double perovskite nanocrystals would be considered as a single-component phosphor for warm-white lighting.