A highly efficient surface-emitting light source enabled by silicon nitride photonic crystal cavities coupled with...

The development of highly efficient surface-emitting light sources has catalyzed significant progress in integrating advanced light-emitting materials with photonic structures. In this study, we present a highly efficient surface-emitting light source achieved by coupling perovskite quantum dots (CsPbBr₃ QDs) with silicon nitride (Si₃N₄) photonic crystal (PhC) cavities. The Si₃N₄ PhC cavity is designed with a hexagonal lattice of air holes featuring gradient radii, providing strong field localization and supporting highly directional emission near the Γ point within the light cone. Through the Purcell effect, which accelerates the spontaneous emission rate, and the redistribution of emitted light into the vertical direction, the photoluminescence (PL) intensity is increased by 12-fold. Moreover, the cavity enables efficient light extraction through small-angle vertical emission, enabling the majority of emitted light to be collected within a narrow angular range of ±3.6°, concentrated near the surface normal. Furthermore, embedding the QDs within a polymethyl methacrylate (PMMA) matrix enhances their environmental stability without compromising optical performance. These findings underscore the potential of this hybrid system as a highly efficient light emitter, offering promising applications in next-generation optoelectronic devices.