Applied Physics Letters · 2014 · 2.7K citations · 22 references
Natural SciencesMaterials EngineeringMaterials ScienceElectronic MaterialsSemiconductor MaterialsThin FilmsDefects In Electronic MaterialsPerovskite MaterialsPhotovoltaic MaterialsSemiconductor DefectsSolar Cell MaterialsSolar CellsDefect PhysicsDiffusion LengthElectron DiffusionHalide PerovskitesIntrinsic DefectsOpen-circuit VoltagePerovskite SemiconductorsPerovskite Solar Cells
Thin-film solar cells based on Methylammonium triiodideplumbate (CH3NH3PbI3) halide perovskites have recently shown remarkable performance. First-principle calculations show that CH3NH3PbI3 has unusual defect physics: (i) Different from common p-type thin-film solar cell absorbers, it exhibits flexible conductivity from good p-type, intrinsic to good n-type depending on the growth conditions; (ii) Dominant intrinsic defects create only shallow levels, which partially explain the long electron-hole diffusion length and high open-circuit voltage in solar cell. The unusual defect properties can be attributed to the strong Pb lone-pair s orbital and I p orbital antibonding coupling and the high ionicity of CH3NH3PbI3.
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