Efficient Perovskite Solar Cells Fabricated by Co Partially Substituted Hybrid Perovskite

In the past years, hybrid perovskite materials have attracted great attention due to their superior optoelectronic properties. In this study, the authors report the utilization of cobalt (Co 2+ ) to partially substitute lead (Pb 2+ ) for developing novel hybrid perovskite materials, CH 3 NH 3 Pb 1‐ x Co x I 3 (where x is nominal ratio, x = 0, 0.1, 0.2 and 0.4). It is found that the novel perovskite thin films possess a cubic crystal structure with superior thin film morphology and larger grain size, which is significantly different from pristine thin film, which possesses the tetragonal crystal structure, with smaller grain size. Moreover, it is found that the 3d orbital of Co 2+ ensures higher electron mobilities and electrical conductivities of the CH 3 NH 3 Pb 1‐ x Co x I 3 thin films than those of pristine CH 3 NH 3 Pb 4 thin film. As a result, a power conversion efficiency of 21.43% is observed from perovskite solar cells fabricated by the CH 3 NH 3 Pb 0.9 Co 0.1 I 3 thin film. Thus, the utilization of Co, partially substituting for Pb to tune physical properties of hybrid perovskite materials provides a facile way to boost device performance of perovskite solar cells.