Facile solution synthesis of Bi<sup>3+</sup>/Yb<sup>3+</sup> ions co-doped Cs<sub>2</sub>Na<sub>0.6</sub>Ag<sub>0.4</sub>InCl<sub>6</sub> double perovskites with near-infrared emission
Guodong Zhang, Yi Wei, Peipei Dang, Hui Xiao, Dongjie� Liu, Xinke Li, Ziyong Cheng, Jun Lin
Abstract
Double perovskites have attracted wide attention due to their low toxicity and good thermal stability. Doping with active elements is a promising method to endow perovskites with excellent optical, electrical or magnetic properties. Herein, a facile aqueous solution method is developed to synthesize Bi3+-Yb3+ co-doped Cs2Na0.6Ag0.4InCl6 double perovskite. Besides the intrinsic warm white self-trapped exciton (STE) emission that originated from the Cs2Na0.6Ag0.4InCl6 host, the samples also exhibit a strong near-infrared emission assigned to the 2F5/2 → 2F7/2 transition of octahedral coordinated Yb3+ ions upon excitation with ultraviolet light. The optimized sample shows a markedly high photoluminescence quantum yield of 84.7%. The photophysical studies such as photoluminescence (PL) and photoluminescence excitation spectra, temperature-dependent PL spectra, and PL decay curves reveal that the strong Yb3+ emission is attributed to the energy transfer from STEs to the Yb3+ ions. Finally, the lead-free double perovskite phosphor-converted LED containing visible and NIR regions was fabricated, with 8.92 mW output power at 100 mA drive current. The results show the great potential of the as-prepared crystals in optoelectronics applications.