Efficient, symmetric oligomer hole transporting materials with different cores for high performance perovskite solar cells.

Novel symmetric oligomer hole transporting materials (HTMs) incorporating 3,4-ethylenedioxythiophene (EDOT) and 2,1,3-benzothiadiazole (BTD) cores have been synthesized and tested for high performance perovskite solar cells. A maximum energy conversion efficiency of 14.23% has been achieved by employing with the electron donating EDOT unit as the core, which is comparable to that of the traditional (14.55%).