Development of electron and hole selective contact materials for perovskite solar cells

Nowadays, both n-i-p and p-i-n perovskite solar cells (PSCs) device structures are reported to give high performance with photo conversion efficiencies (PCEs) above 20%. The efficiency of the PSCs is fundementally determined by the charge selective contact materials. Hence, by introducing proper contact materials with good charge selectivity, one could potentially reduce interfacial charge recombination as well as increase device performance. In the past few years, copious charge selective contact materials have been proposed. Significant improvements in the corresponding devices were observed and the reported PCEs were close to that of classic Spiro-OMeTAD. This mini-review summarizes the state-of-the-art progress of typical electron/hole selective contact materials for efficient perovskite solar cells and an outlook to their development is made.