Ultrastable Perovskite Nanocrystals in All‐Inorganic Transparent Matrix for High‐Speed Underwater Wireless Optical Communication

Abstract The key features of lead halide perovskites, including short emission lifetime and excellent luminous efficiency in the green emission region, perfectly match the strict requirements of underwater wireless optical communication (UWOC). However, the poor stability of perovskite nanocrystals (NCs) restricts its application under water and no relevant application research has been reported. Here, extremely stable CsPbBr 3 NCs in all‐inorganic amorphous glass synthesized by all‐solid reaction without any organic ligand are reported. The products achieve high photoluminescence quantum yield (70%) as well as excellent stability toward water, thermal treatment (200 °C in air) and intensive laser irradiation (3.6 kW cm −2 ). The authors also raise that the refraction index could strongly influence the lifetime values according to the oscillator strength of radiative transitions. The large refraction index of the glass matrix enhances the radiative transition rates of CsPbBr 3 NCs (decay time 3.22 ns). At last, the first application of perovskite NCs for UWOC is demonstrated, achieving a bandwidth as high as 180 MHz and data rates of 185 Mbps.