Pressure‐assisted cooling to grow ultra‐stable <scp>Cs₃Cu₂l₅</scp> and <scp>CsCu₂l₃</scp> single crystals for solid‐state lighting and visible light communication

Abstract

Abstract Owing to the excellent optical properties, white light‐emitting diodes (WLEDs) based on metal halide perovskites have attracted great attention as promising light source for solid‐state lighting and wireless visible light communication (VLC). However, the instability and toxicity of classic hybrid lead halides hinder their practical applications. Here, a pressure‐assisted cooling method is developed to grow lead‐free Cs 3 Cu 2 I 5 and CsCu 2 I 3 single crystals, which exhibit more excellent stability, larger size and uniform orientations in comparison with pressure‐free cooling method. Then, both single crystals are used as the emitters of WLEDs without encapsulation, exhibiting a high Color Rendering Index of 91, a decent Commission Internationale de l'Eclairage coordinate of (0.33, 0.33), a proper Correlated Color Temperature of 5436 K, as well as an excellent 1350‐h operating stability at atmosphere. Furthermore, the prepared WLEDs are utilized in wireless VLC, which possesses a −3 dB bandwidth of 10.1 MHz. image