Comparing FAMACs Perovskite Solar Cells to FADMACs Perovskite Solar Cells Through Transient Measurements

Organic-inorganic metal halide perovskite solar cells (PSCs) show great promise in the photovoltaic industry due to their low cost and intriguing photophysical properties. Some of these intriguing properties include high power conversion efficiencies, large diffusion lengths, and slow hot carrier cooling. Perovskite solar cells have reached power conversion efficiencies as high as 25.5% for a single-junction but the material degrades when it is exposed to air, water, or light. Overcoming degradation and improving power conversion efficiencies are key to commercializing PSCs. Understanding the carrier dynamics is crucial to surmounting these barriers. This study aims to compare the performance of FAMACs to FADMACs perovskite solar cells using spectroscopic and transient electro-optic measurements.

In this study, I compare the photoluminescence, transient photovoltage lifetimes, charge transport time, charge carrier density, and diffusion length of the triple cation devices. The FADMACs cell displays a power conversion efficiency of 18.22% while the FAMACs cell displays a power conversion efficiency of 14.17%. The FADMACs device has a larger bandgap compared to the FAMACs device. Both samples exhibit a tri-exponential photovoltage decay however, the FAMACs device exhibits shorter lifetimes. Also, the FAMACs cell exhibits shorter diffusion lengths than the FADMACs cell. The longer lifetimes and diffusion lengths imply a lower defect density and could explain the increase in performance of the FADMACs device. Finally, the validity of the measurements is discussed and compared to similar studies. This study adds to the ongoing investigation of charge carrier dynamics in PSC, but further insight is required for the commercialization of the cells.