Flexible cesium lead halide CsPbX3@SiO2 (X = Cl, Br, I and their mixtures) perovskite nanocrystal films

A centrifugally casting process was developed to prepare inorganic cesium lead halide CsPbX3 @SiO2 (X = Cl, Br, I and their mixtures) perovskite nanocrystal (PNC) films with high photoluminescence performance. By this costless solution-processing method, the obtained CsPbX3 @SiO2 nanocrystal (NC) films exhibit the strong emission covering the whole visible light range with high photoluminescence quantum yields (PLQYs) of 94.0 %, 33.7 % and 10.9 % for the green, blue and red emission, respectively. By encapsulating CsPbX3 NCs with silica, the CsPbX3 @SiO2 NC films achieve remarkably enhanced stability against the ultraviolet (UV) irradiation, the thermal shock and the moist environment, especially for the CsPbBr3 @SiO2 NC films. Through using the flexible substrates such as polyethylene-terephthalate (PET), the CsPbX3 @SiO2 NC films show the excellent scalable and bendable capability. In addition, the LED devices assembled with the CsPbX3 @SiO2 NC films display a broader gamut and a highest color rendering index of 93.4. The achievement of the flexible CsPbX3 @SiO2 NC films with high photoluminescence performance and better stability by the centrifugal method used here, opens a gate for practical applications of PNCs in the flexible luminescence and display devices.