Low‐Cost Carbazole‐Based Hole‐Transport Material for Highly Efficient Perovskite Solar Cells

Abstract A low‐cost carbazole‐based small‐molecule material, 1,3,6,8‐tetra( N , N ‐ p ‐dimethoxyphenylamino)‐9‐ethylcarbazole, was designed and synthesized through a facile three‐step synthetic route. The material was characterized and applied as a hole‐transport material (HTM) for low‐temperature‐processed planar perovskite solar cells (PSCs). Devices based on this new HTM exhibit a high power‐conversion efficiency of 17.8 % that is comparable to that of PSCs based on the costly 2,2′,7,7′‐tetrakis[ N , N ‐di(4‐methoxyphenyl)amino]‐9,9′‐spirobifluorene (Spiro‐OMeTAD) (18.6 %) .