Enhanced charge collection and stability in planar perovskite solar cells based on a cobalt(iii)-complex additive

Abstract

Chemical doping has emerged as a favourable method for tuning the electrical properties of the hole-transport layer (HTL) in perovskite solar cells. Herein, we demonstrated an efficient dopant, cobalt(III) complex tris[2-((1H-pyrazol-1-yl)-4-tert-butylpyridine)cobalt(III)tris(bis(trifluoromethylsulfonyl)imide)] (FK209), which exhibited concentration distribution characteristics. The interfacial charge collection is demonstrated to be enhanced. We obtained the optimal power conversion efficiency (PCE) of 17.34% by optimizing the Co-complex doping ratio. Moreover, we found that the doping of Co-complex into the HTL significantly improved the stability under a sensitive atmosphere.