Covalent Dual-Shell-Encapsulated Perovskite Quantum Dots for Blue-Light-Resistant, Highly Stable Pixel Fabrication

Perovskite quantum dots (PQDs) are promising candidates for next-generation displays but suffer from poor stability during manufacturing and application. Owing to their intrinsic soft lattice and weak surface ligand-lattice bonding, PQDs degrade easily under light, heat, humidity, and oxygen. Herein, we propose an inorganic-organic covalently bonded dual-shell encapsulation strategy for PQDs. An inorganic inner shell locks the crystal surface to ensure structural stability, while the inorganic shell links to an organic acrylate polymer shell via Si-O-Si bonds to improve dispersion and chemical cross-linking, thereby enhancing the encapsulation of individual PQDs. Benefiting from this strategy, PQDs retain more than 90% of their pristine fluorescence lifetime and maintain stable colloidal dispersion even after 30 days of storage in polar solvents. Under 75% relative humidity, ambient air, and 10,000 cd/m² blue light irradiation for 100 h, the fluorescence intensity of the prepared PQD film remained at 96.081 ± 0.019%, compared to 40.037 ± 0.024% for the pristine sample group, indicating enhanced blue light resistance. Carboxylic acid groups in the organic shell precisely passivate surface defects, boosting the photoluminescence quantum yield (PLQY) from 59.1% to 98.3%. Utilizing alkenyl double bonds in surface ligands and their photoinitiated cross-linking, 5 μm high-resolution pixel patterning is achieved. The PQD-based color conversion layer exhibits excellent stability, delivering a brightness of 1,468,161.5 cd/m² under excitation from a 445 nm blue-light chip and a 67.7-year operational lifetime at 100 cd/cm², which is 100-fold longer than that of unencapsulated PQDs. This strategy enables the practical application of PQDs in high-resolution backlight displays.