Investigations on interfacial complex dynamic processes of Er-BiFeO3 based perovskite solar cell heterostructures

In the present investigations, we critically examine the response of thickness variation of the photoactive layer on I-V characteristics of the final optimized Er-doped BiFeO₃ (Er-BF) designed devices (Er: 0 %, 4 %, 8 %, and 12 %). The recombination rate, energy band diagrams obtained at a final simulated thickness of the absorber and at the back contact metal work function were investigated for the purpose of barrier formation analysis. To establish the presence of deep defects in the perovskite based heterostructure devices, the measurements of respective designed devices related to capacitance–voltage (C-V), Mott-Schottky (MS) (1/C²-V), and conductance-voltage (G-V) characteristics were thoroughly performed and examined. The change in capacitance (or dielectric constant) induced thermally in the respective designed devices was investigated with the temperature-dependent capacitance-frequency (C-f) characteristics performed under the illumination and dark conditions, respectively. Further, the voltage dependent Nyquist plots were studied. Overall, this work provides critical insights into the impedance response of doped BiFeO₃ absorber-based designed perovskite solar cells (PSCs) with cell structure FTO/ZnO/Er-BF/Spiro-OMeTAD/Au. It further facilitates the understanding of various complex electrical processes taking place at the different interfaces during the device operations which are significant for the better optimization and play crucial role in enhancing the overall photovoltaic performance of PSCs.