Cs_2Zr_(1−x)Te_xCl_6 Perovskite Microcrystals with Ultrahigh Photoluminescence Quantum Efficiency of 79.46% for High Light Efficiency White Light Emitting Diodes

摘要

Recently, lead-free materials with stable photoluminescence (PL) at room temperature, such as vacancy-ordered double perovskites have drawn wide attention. Herein, Te4+-doped all-inorganic lead-free Cs2Zr1-xTexCl6 perovskite microcrystals (MCs) are reported. The obtained pure Cs2ZrCl6 perovskite MCs exhibit a blue emission, while Cs2Zr1-xTexCl6 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 P-3(1) of Te can be partially frozen at the low temperature regarding Cs2Zr1-xTexCl6 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 Cs2Zr1-xTexCl6 perovskite MCs powder with a commercial near-UV LED (NUV-LED) chip (450 nm). The results suggest that Te4+-doped all-inorganic lead-free perovskite MCs show great potential in the next-generation solid-state lightings.