Synthesis and luminescence of ultrasmall CsPbBr₃ nanocrystals and CsPbBr₃/Cs₄PbBr₆ composites by one-pot method

All-inorganic perovskites CsPbX₃ (X = Cl, Br, I) have attracted worldwide interest due to their excellent luminescent performances. Meanwhile, Cs₄PbBr₆ have been studied because they can enhance the luminescent efficiency and stability of CsPbBr₃. Herein, we introduced a microfluidic method based on room-temperature supersaturated recrystallization to synthesize blue-emitting CsPbBr₃ nanocrystals (NCs) and green-emitting CsPbBr₃/Cs₄PbBr₆ NCs. The ultrasmall CsPbBr₃ NCs emitted at a deep blue wavelength of 461 nm with the full width at half maximum (FWHM) of 15 nm. transmission electron microscopy (TEM) results demonstrated that ultrasmall CsPbBr₃ NCs with the average particle size of 3.8 nm were synthesized and the CsPbBr₃ NCs were crystallized as monoclinic structure. X-ray photoelectron spectrometer (XPS) analysis suggested that ultrasmall CsPbBr₃ suffered from V_Br defect and the surface passivation of Cs₄PbBr₆ possessed a low level of V_Br defect density. The lifetime of CsPbBr₃/Cs₄PbBr₆ was much longer than that of CsPbBr₃. The results showed that ultrasmall CsPbBr₃ NCs can be regarded as a source of blue-emitting material and CsPbBr₃/Cs₄PbBr₆ NCs had a better stability. Graphic abstract: [Figure not available: see fulltext.].