Water- and Light-Stable Red-Emitting Perovskite Quantum Dots by Silane-Siloxane Dual Encapsulation for Full-Color Displays

Red-emitting perovskite quantum dots (Red-PQDs) are highly crucial components for achieving full-color PQD-based color-converters. However, red-PQDs are particularly prone to degradation due to their highly ionic bonding nature, phase instability, and insufficient surface passivation. Developing highly stable red-PQDs in diverse environments remains a critical barrier to their practical implementation as light emitters in displays. Here, we report a long-term stable red-PQD through a dual encapsulation strategy involving the introduction of silane-based ligands and a siloxane-based encapsulation matrix. This approach enables the preservation of photoluminescence quantum yield (PLQY) > 60 days in air and water and under continuous blue light irradiation. The silane-based ligands facilitate surface functionalization and passivate cationic defects on the red-PNCs, enabling effective chemical encapsulation within the siloxane hybrid matrix. By optimizing the silane ligand composition, we achieved a high PLQY alongside pure red emission. Furthermore, the underlying mechanism of enhanced stability was elucidated through optical-, chemical-, and molecular-scale analyses. As a proof of concept, we demonstrate red-emitting and white-emitting color-converting films that maintain stability for >60 days in water. These findings underscore the effectiveness of our strategy and highlight the potential of red-PQDs for stable color-converting layers in displays.