New insight on the open‐circuit voltage of perovskite solar cells: The role of defect‐density distribution and electric field in the active layer

In this article, we study the J–V characteristic of a perovskite solar cell (PSC) prepared by the two-step method. PSCs were fabricated by methylammonium lead iodide using the sequential deposition method. We describe J–V curves using a modified dynamic electrical model based on an asymmetric electric field. In addition, we simulated the PSCs by solar cell capacitance simulator package to investigate the role of trap-density distribution in cell performance. The experimentally optimized device shows an enhancement in the open-circuit voltage (VOC) from 1.08 to 1.21 V. Simulation results show that the increase in VOC up to 1.15 V is corresponding to a trap-density of 2.38×1015 cm−3. However, these results predict that a decrease in the trap-density can increases the VOC and FF up to 1.19 V and 79% while the modified dynamic electrical model gives the J–V characteristic as well as experimental results. Our results suggest that the increase in VOC can be attributed to the asymmetric electric field at the interface of the perovskite layer.