Cobalt Salt as Efficient Dopant for Spiro-MeOTAD in Cesium-Containing Planar Perovskite Solar Cells.

The chemical doping is an effective strategy to improve the charge transport property of hole transport material (HTM). Herein, tris(2-(1H-pyrazol-1-yl)pyridine]cobalt(III) (FK102) doped 2,2,7,7-tetrakis(N, N-di-p-methoxyphenylamine)-9,9-spirobifluorene (spiro-MeOTAD) as HTM for semi-transparent cesium-containing planar perovskite solar cell (Cs0.1MA0.9PbI3) is demonstrated. Incorporating FK102 realizes efficient doping, which improves the mobility of HTM from 3.948 × 10-3 m2V-1s-1 to 2.22 × 10-2 m2V-1s-1, which is 5.6 times enhancement. As a result, the power conversion efficiency (PCE) is largely improved from 7.58% to 10.09% due to the improved hole transport and extraction.