Pushing the certified efficiency of inverted perovskite solar cells beyond 24 %: A review

Over the past five years, the certified efficiency of inverted perovskite solar cells (PSCs) has increased rapidly and surpassed that of regular PSCs. To date, the certified efficiency of inverted PSCs has reached 27 ​%, whereas that of regular PSCs has been stagnant at 26 ​% for almost two years, indicating that inverted PSCs have more potential to further overcome their current efficiency. However, only a few research teams have realized a certified efficiency of >24 ​% for inverted PSCs. For the development of this industry, more relevant talents are needed to master the latest technology. This review explores the recent advancements in inverted PSCs with certified efficiencies higher than 24 ​% and summarizes the key factors (including the optimization of carrier transport layers, reduction of perovskite crystals and interfacial defects, and regulation of the energy band) for fabricating high-efficiency inverted PSCs. Based on these key factors, some perspectives are proposed to further improve the performance and stability of inverted PSCs, thereby promoting their commercial development.