Improved conversion efficiency of perovskite solar cells converted from thermally deposited lead iodide with dimethyl sulfoxide-treated poly(3,4-ethylenedioxythiophene) poly(styrene sulfonate)

The thermal deposition of lead iodide (PbI2) results in the changes in the contact surface of a poly (3,4-ethylenedioxythiophene) poly (styrene sulfonate) (PEDOT:PSS) layer of solar cells (SCs). The changed contact surface of PEDOT:PSS layer after the thermal deposition of PbI2 remains stable after PbI2 is converted into perovskite and leaves the degraded perovskite/PEDOT:PSS interface. The degraded perovskite/pristine PEDOT:PSS interface leads to a low power conversion efficiency (η%) of SCs at 3.84%. The properties of the contact surface of the PEDOT:PSS layer during the thermal deposition of PbI2 can be retained by treating PEDOT:PSS with dimethyl sulfoxide (DMSO) and maintain the perovskite/PEDOT:PSS interface in good condition after PbI2 is converted. Perovskite SCs with DMSO-treated PEDOT:PSS substantially improves η% from 3.84% to 9.58%.