Cs<sub>2</sub>Zr<sub>1−</sub><i><sub>x</sub></i>Te<i><sub>x</sub></i>Cl<sub>6</sub> Perovskite Microcrystals with Ultrahigh Photoluminescence Quantum Efficiency of 79.46% for High Light Efficiency White Light Emitting Diodes
Zhilin Li, Zhihui Rao, Qiaoqiao Li, Liujiang Zhou, Xiujian Zhao, Xiao Gong
Abstract
Abstract Recently, lead‐free materials with stable photoluminescence (PL) at room temperature, such as vacancy‐ordered double perovskites have drawn wide attention. Herein, Te 4+ ‐doped all‐inorganic lead‐free Cs 2 Zr 1− x Te x Cl 6 perovskite microcrystals (MCs) are reported. The obtained pure Cs 2 ZrCl 6 perovskite MCs exhibit a blue emission, while Cs 2 Zr 1− x Te x Cl 6 perovskite MCs show a broad and strong yellow emission with ultrahigh photoluminescence quantum yield (PLQY) up to 79.46% at room temperature. The structure and optical properties of perovskite MCs are investigated in detail by experiments and theoretical calculations. The mechanism that 3 P 1 of Te can be partially frozen at the low temperature regarding Cs 2 Zr 1− x Te x Cl 6 perovskite MCs is proposed. White light emitting diodes (WLEDs) with a color coordinate of (0.344, 0.333), a correlated color temperature of 4959 K, a color rendering index (Ra) of 74.8, and a high light efficiency of 91.16 lm W −1 , are fabricated by the prepared Cs 2 Zr 1− x Te x Cl 6 perovskite MCs powder with a commercial near‐UV LED (NUV‐LED) chip (450 nm). The results suggest that Te 4+ ‐doped all‐inorganic lead‐free perovskite MCs show great potential in the next‐generation solid‐state lightings.