In-situ stabilization strategy for CsPbX3-Silicone resin composite with enhanced luminescence and stability

Inorganic lead halide perovskite (CsPbX3, X = Cl, Br, I) nanocrystals (LHP NCs) are promising materials for a variety of photonic or optoelectronic applications. Yet their intrinsic instability issue remains a critical challenge to overcome. Encapsulation of ionic LHP NCs in inert matrices such as polysiloxanes has been proved as an effective stabilization strategy, but the ex-situ synthesis of LHP NCs remains a limiting factor. Herein, an in-situ stabilization strategy that involves synergistic crystallization of LHP NCs and crosslinking of addition-type silicone oil precursors is reported. This simple, yet general stabilization strategy can effectively passivate the trap defects and increase the radiative recombination of CsPbX3 NCs, which leads to a significant enhancement of the photoluminescence quantum yield (PLQY) from 68% for the solution to 82% for the composite powder. A series of CsPbX3-silicone resin composites with tunable emission wavelength ranging from 445 to 613 nm can be simply obtained by using suitable halide salts. Because of the protection of the silicone resin, the CsPbBr3-silicone resin composites exhibit high stability against moisture or heat in the ambient environment and could still keep their photoluminescence (PL) emission after being kept in air for one year or immersed in water for two months. Such composites have been used as functional downconverters in white LEDs that demonstrated a 92.7% color gamut coverage of Rec.2020. This work provides an alternative approach to solve the challenging stability issue of perovskite NCs.