New insights into active-area-dependent performance of hybrid perovskite solar cells

The morphology of hybrid perovskite thin films depends strongly on the processing parameters due to its complex crystallization kinetics from a solution to solid perovskite halide phase. It is also profoundly sensitive to the device area of the deposited thin film, and hence reproducible photoconversion efficiency (PCE) remained a bottleneck for the fabrication of efficient photovoltaic devices having large active area. The present work focuses on the investigations of the relationship between perovskite ink concentration-dependent quality of the perovskite overlayer and PCE of the perovskite solar cells (PSC) while scaling-up process. The field-emission scanning electron microscopy images revealed that the surface coverage of perovskite overlayer depends on the concentration of perovskite solution and device area. The active-area-dependent current density (J)-voltage (V) and external quantum efficiency measurements identify morphology-dependent variation in charge-transport/recombination pathways. We confirmed that among different precursor concentrations, 40 wt% perovskite ink is suitable to produce uniform perovskite overlayer over 1 cm ² . As a result, highly reproducible PCE ~ 13% has been achieved for the PSC having an active area of 1 cm ² . Overall, our findings significantly provide new insights into the active-area-dependent PCE of PSC.