Simultaneous enhancement of luminescence and stability of CsPbBr₃ perovskite nanocrystals via formation of perhydropolysilazane-derived nanopatterned film

In this paper, we report the creation of robust and bright visible light-emitting perhydropolysilazane (PHPS)-derived nanopatterned CsPbBr₃ perovskite nanocrystal (PNC)-SiO₂ films. The CsPbBr₃-SiO₂ films exhibit improved stability against heat exhibiting 35.4% of the initial photoluminescence (PL) intensity after 160 °C heat-treatment and improved stability against water showing 92.6% of the initial PL intensity even after 30 days’ water immersion. In addition, the introduction of nanocylinder and nanocone patterns to the PHPS-derived CsPbBr₃-SiO₂ film resulted in 3.71 and 4.62-fold PL enhancement compared with the planar counterpart. The time resolved PL analysis and finite-difference time domain calculations indicate that the improvement of optical performance of the nanopatterned CsPbBr₃-SiO₂ films could be attributed to the enhanced absorption and emission via Mie resonance excitation. When the nanopatterned CsPbBr₃-SiO₂ film was combined with a blue light-emitting diode (LED), some of the blue light from the LED was converted into green light with high light conversion efficiency (72.3%). Along with the improved stability, the enhanced luminescence of the nanopatterned CsPbBr₃-SiO₂ films further extends their applicability for use in display devices with wide color gamut.