Direct Hot-Injection Synthesis of Lead Halide Perovskite Nanocubes in Acrylic Monomers for Ultrastable and Bright Nanocrystal-Polymer Composite Films.

In recent years, lead halide perovskite nanocrystals (NCs) have attracted significant attention in both fundamental research and commercial applications because of their excellent optical and optoelectrical properties. However, the protective ligands on the surface of the perovskite NCs could be easily removed after the tedious process of centrifugation, separation, and dispersion, which greatly hampers their stability against light, heat, moisture, and oxygen and limits their practical applications. Here, we report a new post-processing free strategy (i.e., without centrifugation, separation, and dispersion process) of using an ultraviolet (UV)-polymerizable acrylic monomer of lauryl methacrylate as the solvent to synthesize CsPbBr NCs, and then adding polyester polyurethane acrylate oligomer, monomer (IBOA), and initiator for direct UV polymerization to fabricate NC-polymer composite films. These films exhibited an improved photoluminescence quantum yield (85-90%) than classic NC films (40-50%), which were processed using octadecene (ODE) as the solvent for NC synthesis and postprocessed for UV polymerization. Significantly, the as-fabricated films by post-processing free strategy exhibited excellent photostability against strong Xe lamp illumination; while the other films using classic methods were quickly photodegraded. Meanwhile, these NC-polymer composite films showed good stability against moisture and heating when aging in water at 50 °C for over 200 h. These films, along with KSiF:Mn (KSF) phosphor emitters, were used as downconverters for blue light-emitting diodes in liquid-crystal displays with a wide color gamut of 115% in the International Commission on Illumination (CIE) 1931 color space. This work provides a facile and effective strategy for the preparation of ultrastable and bright color-conversion NC films for the development of the next-generation wide color gamut displays.