Purcell-enhanced Bright and Dark Exciton Emission from Perovskite Quantum Dots in Micro-ring Resonators

Abstract

Colloidal quantum dots (QDs) integrated with waveguide-coupled dielectric resonators are promising building blocks for compact on-chip light sources. However, deterministic placement of QDs with strong mode overlap at the desired location remains a challenge. Here, we demonstrate a simple and scalable strategy for integrating colloidal QDs with a waveguide-coupled Si3N4 micro-ring resonator platform and for controlling the radiative dynamics of both bright and dark excitons via Purcell enhancement. We use strongly quantum-confined CsPbBr3 QDs, which exhibit bright-exciton emission at room-temperature, while emission at cryogenic temperatures originates from both bright and dark excitons. The CsPbBr3 QDs are selectively retained on the Si3N4 micro-ring cavities through a spin-coating/rinsing process, enabling efficient overlap with whispering-gallery modes and routing of the emission through integrated waveguides. We confirm accelerated decay of emission from both bright and dark excitons for CsPbBr3 QDs coupled to the micro-ring cavities. These results demonstrate an effective route to integrate colloidal QDs with Si3N4 micro-ring cavities and to leverage cavity-enhanced emission in scalable integrated photonic devices.