Progress and Challenges of Chloride–Iodide Perovskite Solar Cells: A Critical Review

Chloride–iodide perovskites have received substantial interest due to their better photovoltaic performance compared to pure iodide ones. The superior properties of chloride–iodide perovskites boost photovoltaic performance. However, quantifying the Cl composition in perovskite films remains challenging. Hence, it is not easy to correlate the Cl quantity with the improved photovoltaic performance. Considering this critical issue, it is still necessary to determine the correlation between the Cl quantity and the improved photovoltaic performance to solve this puzzle. Here, a critical review is presented showcasing the significant impacts of the Cl quantity on chloride–iodide perovskites and related solar cell devices. This review provides an up-to-date picture of different strategic methods to overcome the challenges of Cl incorporation in I-based perovskites, aiming to improve photovoltaic performance. Finally, some valuable remedies are prescribed for potential future research strategies to study the photovoltaic performance of chloride–iodide perovskite solar cells. Hopefully, this review will be a noteworthy scientific contribution to the advancement of the continuous progress of perovskite solar cells.