Spatial and Chemical Dual Nano‐Confined Ultrastable Perovskite Quantum Dots Glass Manifesting Exciton Modulation

Abstract Nano‐confined synthesis of perovskite quantum dots (QDs) in solid matrix is emerging as a promising route to solve their long‐standing stability problem. Utilizing sol‐gel derived nanoporous glass as matrix that has high flexibility in chemical composition and pore size, a novel spatial and chemical dual nano‐confined strategy is presented for the synthesis of ultrastable perovskite QDs with tunable composition and bandgap in glass. The findings reveal that the Pb─O bonding is formed at perovskite QDs/glass interface during a nano‐confined chemical vapor deposition (CVD) reaction. In particular, the presence of interfacial chemical bonding is discovered to be critical for passivating surface traps and stabilizing the perovskite QDs during the final densification process (related photoluminescence intensity maintained ≈100% after immersed in aqueous solution for 30 days). Series optical spectroscopy unravels the exciton modulation (80 meV) of perovskite QDs in nanoporous and densified glass related to the unique combination of dual physical and chemistry nano‐confined effect. By shedding light on the nano‐confined growth of functional nanocrystals, the research offers the key paths for fabricating high‐performance perovskite devices.