Facile Van der Waals hBN Encapsulation and Stabilization of Perovskite Quantum Dots Emission

ABSTRACT All‐inorganic perovskite quantum dots (PQDs) are promising room‐temperature single‐photon sources, but practical application is limited by their rapid photodegradation, blinking, and spectral instability at the single‐emitter level. Here, we realize a facile van der Waals (vdW) hexagonal boron nitride (hBN) encapsulation of PQDs that facilitates effective diffusion barriers to avoid rapid photodegradation. Compared with pristine PQDs (P‐PQDs) the hBN encapsulated PQDs (hBN‐PQDs) exhibit a nearly 50‐fold increase in saturation power (P sat ) as well as remarkably suppressed blinking and photobleaching. At single PQD level, it is revealed that the spectral shift and photostability of hBN‐PQDs were essentially reinforced, enabling clear photon antibunching at room temperature. Finally, the preserved spectral emission is maintained even by dissolving the hBN‐PQDs in polar solvents (water and N,N‐dimethylformamide), substantiating the robust optical photostability. The encapsulation strategy provides a promising passivation of PQDs, paving the way toward quantum‐light applications of PQDs.