Towards design of metal oxide free perovskite solar cell paradigm: Materials processing and enhanced device performance

The flexible perovskite thin film solar cell was fabricated using polypyrrole (PPy) as binding agent on ITO-PET flexible substrates. PPy as binding agent and PC61BM as electron transporting material on perovskite (CH3NH3PbI3)-sensitized PEDOT:PSS/ITO-PET substrates formed an efficient flexible perovskites solar cell, which demonstrated the reasonably high solar-to-electricity conversion efficiency (η) of ∼6.38% with high short circuit current (JSC) of ∼15.59 mA/cm2 and open circuit voltage (VOC) of ∼0.852 V under the light illumination of ∼100 mW/cm2 (1.5 AM). The transient photocurrent and photovoltage studies explained the improved charge transport time, efficient diffusion coefficient, diffusion length and high charge collection efficiency of the fabricated flexible perovskite solar cells. These enhancements might attribute to active PPy as binding agent along with electron transporting material of PC61BM. Thus, a reduced recombination and the improved charge transfer properties might render PPy as a cost-effective competitor in the flexible perovskites solar cell.