Charge transporting materials for perovskite solar cells

Perovskite solar cells (PSCs) have made great progress since 2009 and become the focus of current research. As an important part of PSCs, charge transporting materials play an important role in the performance of the devices. In this review, we introduce the evolution of electron and hole transporting materials in PSCs in recent years and summarize some typical charge transporting materials and their applications in PSCs. For electron transporting materials, metal oxides (TiO 2 , SnO 2 and ZnO) and organic materials (fullerenes, non-fullerenes and their derivatives) are the most widely used materials in PSCs. For hole transporting materials, small molecule spiro-OMeTAD (2,2′,7,7′-Tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9′-spirobifluorene), polymer PEDOT:PSS (poly (3,4-ethylenedioxythio- phene): polystyrene sulfonate), PTAA (poly-[bi(4-phenyl)] (2,4,3-trimethylphenyla-mine)), P3HT (poly (3-hexythiophene)) and inorganic materials (NiO x , CuSCN, CuO) are adopted in PSCs. Finally, different types of charge transporting materials are summarized and their future development is prospected. Graphical abstract