Electrical equivalent circuit (EEC) based impedance spectroscopy analysis of HTM free perovskite solar cells

Monolithic perovskite solar cells (mPSCs) are the multi-layered organic-inorganic hybrid cells that have been focused due to the affordable cost, ease of fabrication, and noteworthy power conversion efficiency (PCE). In this research, we have carried out a systematic study to understand the physical phenomenon inside successive layers of the mPSCs by using the impedance spectroscopy (IS) tool. The analysis has performed under the multiple applied potential to observe the changes in the complex plane (Nyquist) plot and their effect on the performance of different layers of the mPSCs. The IS analysis for each successive layer of the porous electrode has also conducted to distinguish their contribution to the Nyquist plot. The effect of the carbon layer and perovskite has been validated by performing the IS analysis in sequence after the deposition of each of these layers. The internal electrical processes at the interfaces of the layers of mPSC devices have been related to produce an electrical equivalent circuit (EEC) of an overall mPSC device. The data of the optimized mPSCs with power conversion efficiency over 13% has been used to perform the EEC analysis, where multi-cations perovskite film has been employed as a light absorber.