10.3% Efficient CuIn(S,Se)2 Solar Cells from DMF Molecular Solution with the Absorber Selenized under High Argon Pressure

Recently, a 22.6% efficiency CIGS solar cell fabricated from co-evaporation has been reported, exceeding the efficiency of polysilicon solar cells. However, the high cost and low throughput make it hard for large scale manufacturing. Here, we report that highly efficient copper indium sulfoselenide solar cells can be fabricated from single DMF molecular precursor solution without any etching when the CIS precursor film was annealed with selenium vapor under 0.16 MPa argon pressure. A power conversion efficiency of 10.3% with a current density of 35.5 mA/cm2, an open circuit voltage of 0.44 V, and a fill factor of 65.3% was achieved without an antireflective coating. The enhanced device performance is due to a densely packed top absorber layer without any voids by a 0.16 MPa argon pressure during selenization process. Our results demonstrate that annealing precursor film under increased atmosphere pressure is a new and promising strategy to achieve high performing thin film solar cells, which can be applied to all solution processed thin film chalcogenide solar cell including CIS, CIGS and CZTS.