Silica encapsulation of metal perovskite nanocrystals in a photoluminescence type display application

Perovskite nanocrystals (PeNCs) are attractive in high-color gamut display technology as light converters which can achieve saturated green and red lights, respectively. However, PeNCs are intrinsically fragile against ambient conditions, such as moisture and oxygen and it is hard to maintain their performance in long-term operation. In this work, a new hierarchical encapsulation method is proposed, integrated with surface modification by halide ions protection, nano-scaled encapsulation by in situ capping SiO₂ and embedding into poly (methyl methacrylate) (PMMA) matrix composites, to achieve a stable perovskite light converting composite sheet for LED remote-type encapsulation. The storage stability, as well as the operational stability of perovskite composites, were confirmed by the spectra evolution from encapsulated LEDs with normalized blue emission intensity. The 2D maps of spectra and aging measurement indicate that the silica encapsulation can well protect the PeNCs in the PMMA matrix from the ambient circumstance during a long-term storage process. Additionally, the hierarchical encapsulation for PeNCs/silica/PMMA showed better operational stability than the direct encapsulation of PeNCs/PMMA, and the correspondent Commission Internationale de L'Eclairage color coordinates tracking also indicated more stable color properties, which demonstrates the great potential in photoluminescent display applications. (paper)