摘要
Diminishing surface defect states in perovskite nancx^rystals is a highly challenging subject for enhancing optoelectronic device performance.We synthesized organic/inorganic lead-halide perovskite MAPbBr3(MA=methylammonium)clusters comprising nanocrystals with diameters ranging between 20 and 30 nm and characterized an enhanced photoluminescence(PL)quantum yield(as much as^7 times)by encapsulating the MAPbBr3 with graphene(Gr).The optical properties of MAPbBr3 and Gr/MAPbBr3 were investigated by temperature-dependent micro-PL and time-resolved PL measurements.Density functional theory calculations show that the surface defect states in MAPbBr3 are removed and the optical band gap is reduced by a 0.15 eV by encapsulation with graphene due to partial restoration of lattice distortions.
基金
This work was supported by Basic Science Research Program and National H onor Scientist Program through the National Research Foundation of Korea(NRF)(Nos.2010-0020414,2015R1D1A1A01058332,2018R1D1A1B07043676,2019R1A4A1029237).K.S.K.acknowledges the support from KISTI(Nos.KSC-2018-CRE-0077,KSC-2018-CHA-0057).C.W.M.acknowledges the support from KISTI(Nos.KSC-2018-CRE-0071,KSC-2019-CRE-0139,KSC-2019-CRE-0248).
