Formamidinium lead halide(α-FAPbI3)with a broad light absorption spectrum,has recently received considerable attention in optoelectronic applications.However,the FAI-PbI2-DMSO(DMSO:dimethyl sulfoxide)intermediate ani...Formamidinium lead halide(α-FAPbI3)with a broad light absorption spectrum,has recently received considerable attention in optoelectronic applications.However,the FAI-PbI2-DMSO(DMSO:dimethyl sulfoxide)intermediate anisotropic fibers readily form a non-perovskite phase(δ-FAPbI3)and uncontrolled excess PbI2,which hinders the further increase in the efficiencies of solar cells.Caculations indicate that iodine defects in polycrystalline films would enlarge the perovskite tolerance factor and result in the formation of iodide Frenkel defects.Herein,we introduce a post-treatment technique to heal the as-prepared FAPbI3 thin layer and restrain the notoriousδ-FAPbI3 through vacancy filling.Furthermore,a new intermediate phase of FAI-PbI2-DMSO-FACl led to a high-quality perovskite layer with an enlarged average grain size that exceeded 2μm.Consequently,the power conversion efficiencies of FAPbI3 solar cells were significantly enhanced due to the high crystallity of the pureα-phase perovskite.Therefore,this method can be used to obtain high pure-black perovskite films and efficient solar cells.展开更多
基金This work was supported by the National Key Research and Development Program of China(2017YFE0133800)the Distinguished Youth Foundation of Anhui Province(1708085J09).
文摘Formamidinium lead halide(α-FAPbI3)with a broad light absorption spectrum,has recently received considerable attention in optoelectronic applications.However,the FAI-PbI2-DMSO(DMSO:dimethyl sulfoxide)intermediate anisotropic fibers readily form a non-perovskite phase(δ-FAPbI3)and uncontrolled excess PbI2,which hinders the further increase in the efficiencies of solar cells.Caculations indicate that iodine defects in polycrystalline films would enlarge the perovskite tolerance factor and result in the formation of iodide Frenkel defects.Herein,we introduce a post-treatment technique to heal the as-prepared FAPbI3 thin layer and restrain the notoriousδ-FAPbI3 through vacancy filling.Furthermore,a new intermediate phase of FAI-PbI2-DMSO-FACl led to a high-quality perovskite layer with an enlarged average grain size that exceeded 2μm.Consequently,the power conversion efficiencies of FAPbI3 solar cells were significantly enhanced due to the high crystallity of the pureα-phase perovskite.Therefore,this method can be used to obtain high pure-black perovskite films and efficient solar cells.
