Ultrafast, nonblinking single-photon sources from perovskite quantum dots in plasmonic nanocavities

Achieving strong light-matter interaction to manipulate emission requires integrating colloidal perovskite quantum dots (PQDs) with plasmonic nanocavities, yet this integration is challenged by their vulnerability to polar solvents. We successfully synthesized highly emissive, solvent-resistant CsPbI₃ PQDs and integrated them into nanoparticle-on-mirror structures. This integration enabled a 435-fold reduction in emission lifetime and a 250-fold increase in total emission intensity. Key results include a very short radiative lifetime below 12 picoseconds and a record-high single-photon emission rate exceeding 2.3 × 10⁹ counts per second at room temperature. Notably, we also observed nonblinking single-photon emission with high purity arising from nanocavity-enhanced radiative electron-hole recombination. Finite-difference time-domain simulations confirmed ultrasmall mode volumes of ~3 × 10^-5 (λ/n)³, effectively enhancing spontaneous emission via the Purcell effect. These ultrabright and nonblinking properties highlight the strong potential of this platform for future quantum technology applications.