上海科技大学知识管理系统

The methylamine lead bromide MAPbBr3 and MAPbBr3/(OA)2PbBr4(octylamine lead bromide) of core-shell structure nanoparticles(NPs) were synthesized by ligand-assisted co-precipitation method, and three different sizes NPs were obtained by ultra-high-speed centrifugation, respectively. Then, their morphology and photoluminescence(PL) properties were characterized. The UV-Vis absorption and room temperature PL spectra show that MAPbBr3 and core-shell MAPbBr3/(OA)2PbBr4 NPs both exhibit a significant size-dependent band gap blue shift due to the quantum confinement effect. The low-temperature PL spectra indicate that the shell layer could suppress the phase transition of internal MAPbBr3, and the phonon energy increases with the increasing size. However, compared with MAPbBr3, the phonon energy of the core-shell MAPbBr3 NPs is smaller. The time-resolved PL measurements reveal that the PL decay of MAPbBr3 NPs is dual exponential, and the short lifetime and long lifetime increase from 1.18 ns to 1.55 ns and from 4.49 ns to 9.63 ns with the size increasing, respectively. However, the PL decay of core-shell MAPbBr3/(OA)2PbBr4 NPs is single exponential because the surfaces defects of core were strong passivated by the shell layer, and the long lifetime increases from 7.34 ns to 17.36 ns with the size increasing. The research of the PL properties of MAPbBr3 NPs has important guiding significance to improve the stability and realize high-performance devices. © 2021, Science Press. All right reserved.