Efficient Single-Photon Emission from Buried Perovskite Quantum Dots in Wide-Bandgap Perovskite Thin Films

State-of-the-art single-photon emitters (SPEs) for quantum optics should simultaneously meet key prerequisites of high brightness, photon purity, indistinguishability, and facile routes for deterministic and scalable fabrication. While colloidal perovskite quantum dots (PQDs) have demonstrated great promise as quantum emitters with near transform-limited coherence times through practical synthesis and ligand passivation, inherent challenges remain such as their susceptibility to photodegradation and pronounced sensitivity to environmental factors, which contribute to photoluminescence (PL) intermittency such as spectral diffusion and blinking. Here, we demonstrate a novel material platform of quantum emitters, by growing PQDs into a wide-bandgap 3D perovskite using a one-step solution-processed method. Near-resonant photoluminescence shows resolution-limited narrow linewidth down to 130 μeV, with clear photon-antibunching, suppressed blinking and spectral diffusion for tens of minutes, and a photon count rate of 10⁴/s consistent with unity quantum yield. Direct spectroscopic signatures of the exciton (trion) fine structure are clearly resolved under a magnetic field, and electrical injection of the carriers in PQDs is achieved showing preliminary single-photon emission. Our results pave the pathway for on-chip integration of low-cost single-photon sources for quantum optics.