Single Vs Mixed Organic Cation for Low Temperature Processed Perovskite Solar Cells

Highlights: • Low temperature processed ZnO based single & mixed organic cation perovskite device. • 37% higher PCE in mixed cation perovskite solar cells (PSCs) than single cation ones. • Mixed cation PSCs exhibit significantly reduced photocurrent hysteresis. • Mixed cation PSCs demonstrate three fold higher device stability than single cation PSCs. • Electronic properties are analyzed using Electrochemical Impedance Spectroscopy. - Abstract: The present work reports a comparative study between single and mixed organic cation based MAPbI₃ and MA_0.6FA_0.4PbI₃ perovskite devices fabricated in conjunction with low temperature processed (<150 °C) ZnO electron transport layers. MA_0.6FA_0.4PbI₃ perovskite devices demonstrate 37% higher power conversion efficiency compared to MAPbI₃ perovskite devices developed on the ZnO ETL. In addition, MA_0.6FA_0.4PbI₃ devices exhibit very low photocurrent hysteresis and they are three-fold more stable than conventional MAPbI₃ PSCs (perovskite solar cells). An in-depth analysis on the charge transport properties in both fresh and aged devices has been carried out using electrochemical impedance spectroscopy analysis to comprehend the enhanced device stability of the mixed perovskite devices developed on the ZnO ETL. The study also investigates into the interfacial charge transfer characteristics associated with the ZnO/mixed organic cation perovskite interface and concomitant influence on the inherent electronic properties.