The Role of Oxygen Exposure on the Performance of All-Vapor-Processed Perovskite Solar Cells With CuPC Hole Transport Layers
Methylammonium lead iodide (MAPbI(3)) perovskite solar cells were made using an all-vapor process, including two-step close space vapor transport-processed MAPbI(3) absorber and evaporated copper phthalocyanine (CuPC) hole transport layer (HTL). N-i-p solar cells fabricated entirely in a nitrogen glovebox had poor performance due to s-shaped J-V curves and fill factors (FF) $< $45%. Solar cells exposed to dry air in a desiccator for seven days, or to O-2 flowed into the evaporator during CuPC deposition, had significantly improved performance with reduced or eliminated s-shaped behavior and improved FF up to 72%. Co-planar conductivity measurements show that exposure to dry air, deposition with oxygen, and MoOx capping layers all increase the conductivity of the CuPC HTL. Drift-diffusion simulations show that increasing hole concentration consistent with oxygen doping effects can explain the J-V behavior of the solar cell. Solar cells using spiro-OMeTAD HTLs achieved similar Power Conversion Efficiency but higher V-oc up to 1.01 V. Drift-diffusion simulations show that the V-oc difference can be explained by differences in doping density and valence band position between spiro and CuPC.
WOS:001292785500001
École Polytechnique Fédérale de Lausanne
École Polytechnique Fédérale de Lausanne
École Polytechnique Fédérale de Lausanne
École Polytechnique Fédérale de Lausanne
École Polytechnique Fédérale de Lausanne
École Polytechnique Fédérale de Lausanne
École Polytechnique Fédérale de Lausanne
2024-08-15
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EPFL