Compression packing of CsPbBr3 perovskite quantum dots with boron nitride nanosheets for enhanced stability: A nano-encapsulation strategy

All-inorganic CsPbX 3 (X = Cl, Br, I) perovskite quantum dots (QDs) are vulnerable to adverse factors such as light, high temperature and moisture due to its inherent structural instability, thus limiting its application in the field of optoelectronics . Here, we propose a nano-encapsulation strategy to improve the stability of CsPbBr 3 (CPB) QDs via compression packing of the QDs within two-dimensional flexible BN nanosheets (BNNS). After pre-preparing of CPB/BNNS nanocomposite powder, a dense CPB/BNNS plate is obtained through the compression packing of the powder under the action of external force in a certain mold. By further grinding and sieving, powdery CPB/BNNS particles with the same encapsulation effect are obtained. As compared with CPB/BNNS nanocomposite powder, the plate and particle samples after compression packing can retain the excellent photoluminescence (PL) properties of CPB QDs, while showing greatly improved stabilites in various adverse environments. After compression packing, both of the CPB QDs anchored in BNNS folds and exposed to BNNS interlayers can be well encapsulated in the dense composite structure, which can realizing the successful nano-encapsulation of CPB QDs by BNNS. In addition, the white LED device constructed with CPB/BNNS particle as green phosphor exhibits excellent white light emission and stability.