Transparent Electrode Techniques for Semitransparent and Tandem Perovskite Solar Cells

Inorganic–organic halide perovskite solar cells have attracted significant attention to the photovoltaic community considering their high-efficiency, tunable bandgap, low-cost, and easy fabrication. Perovskite solar cells are especially an attractive top cell partner for tandem applications with silicon bottom cells and other solar cell types with lower bandgap absorbers. For such tandem applications, semitransparent perovskite solar cell techniques with high near-infrared transparency become important, since the incident light needs to efficiently reach the bottom cell. This review article will summarize the status and progress of perovskite-based tandem solar cells development, while focusing on the transparent electrode approaches and techniques. Future directions and challenges of transparent electrodes for semitransparent and tandem perovskite-based photovoltaics will also be discussed.