2, Kyushu Institute of Technology, Kitakyushu, , Japan
Organic-inorganic halide perovskite solar cells (PSCs) have experienced high-speed developments with the highest power conversion efficiency (PCE) of 22.1%, resulting in huge commercial prospects. However, the commonly used electron selective layer (ESL), TiO2, always needs high-temperature post-treatment during its fabrication process, which hinders commercial applications of PSCs. Developing low-temperature processed ESLs with high performances can significantly promote the industrialization of PSCs. In this review, current progress in low-temperature processed ESLs, especially non-TiO2 inorganic, organic materials and quantum dots (QDs), such as SnO2, WOx, C60, BaSnO3, etc., are summarized, including several results of our group. Their fabrication methods, properties, and applications in PSCs are highlighted in this review. We also discuss the importance of further developments of the low-temperature ESLs. These low-temperature processed ESLs will provide more possibilities for designing novel structural PSCs and promoting the commercialization of PSCs.