(185t) Enhancing Efficiency and Morphological Uniformity in Electrochemically Processed Inverted Perovskite Solar Cells

Inverted perovskite solar cells (IPSCs) represent a promising alternative for photovoltaic energy generation due to their high power conversion efficiency (PCE) compared to other solar technologies. Among their advantages is the use of low-temperature chemical processing routes during fabrication, which provides a cost-effective approach with significant potential. These devices employ photoactive materials with a perovskite-type structure (ABX₃) that, upon light absorption, generate electrons and holes. The charge carriers are transported through the electron transport and extraction layer (ETL) and the hole transport and extraction layer (HTL), respectively, until they reach the external circuit, where usable electrical current is produced.

The hybrid perovskite CH₃NH₃PbI₃ has been extensively studied as a photoactive material owing to its ease of fabrication through deposition techniques such as spin coating. While this method has proven effective in small-scale research, it poses limitations for large-area processing. Overcoming these challenges requires alternative deposition strategies capable of enhancing film quality and reproducibility.

In this study, the deposition of the absorber layer was evaluated using electrochemical deposition (ECD) combined with dip-coating on a previously electrodeposited HTL, with the aim of eliminating the use of toxic solvents and simplifying fabrication by avoiding the need for controlled atmospheres. The electrosynthesis of nickel oxide (HTL) and lead oxide layers was carried out through cathodic pulse potentiometry and chronopotentiometry, respectively. The intermediate PbI₂ layer and the final perovskite (CH₃NH₃PbI₃) films were thoroughly characterized by SEM, UV-VIS and photoluminescence spectroscopy, XRD, contact angle measurements, and photovoltaic efficiency tests under simulated solar illumination. The devices exhibited a PCE around 4.5%, with consistent reproducibility across multiple cells. While still below the values obtained by the conventional route, these results highlight that the ECD-based strategy provides a low-cost and controllable fabrication method with the potential to reach comparable efficiencies and stability in perovskite solar cells.