Pressure-assisted cooling to grow ultra-stable Cs3Cu2l5 and CsCu2l3 single crystals for solid-state lighting and visible light communication

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.