Stable perovskite quantum dots encapsulated with polymethyl methacrylate microspheres used in 3D printing and white light emitting diodes

Perovskite quantum dots (PQDs) have excellent optoelectronic properties such as high quantum yield, narrow emission spectrum, and tunable wavelength. They are widely used in display, LED devices, photovoltaics and photo-detection, etc. However, due to the instability of PQDs, they are easily decomposed by humidity or water, which greatly hinders the practical application. To solve this issue, CsPbX3 (X: Cl-, Br-, I-) PQDs encapsulated by polymethyl methacrylate (PMMA) microspheres were prepared by the swelling-shrinkage method. The CsPbBr3 PQDs@PMMA composite microspheres maintain high luminescence intensity and photoluminescence quantum yield after 30 d in water. The fluorescence lifetime of CsPbBr3 PQDs@PMMA can reach 31.36 ns and the quantum efficiency reached 55.67%. CsPbX3 PQDs@PMMA microspheres with different colors can be obtained by changing the molar ratio of halogens. The stability of CsPbBr3 PQDs@PMMA microspheres in air and water were investigated in details. The red, blue and green powders are encapsulated into LED devices with color coordinates of (0.3450, 0.3624), which is close to the ideal white light. The fluorescent powder can also be used in 3D printing fields.