A solution-processed high performance organic solar cell using a small molecule with the thieno[3,2-b]thiophene central unit

A solution processed acceptor-donor-acceptor (A-D-A) small molecule with thieno[3,2-b]thiophene as the central building block and 2-(1,1-dicyanomethylene)-rhodanine as the terminal unit, DRCN8TT, was designed and synthesized. The optimized power conversion efficiency (PCE) of 8.11% was achieved, which is much higher than that of its analogue molecule DRCN8T. The improved performance was ascribed to the morphology which consisted of small, highly crystalline domains that were nearly commensurate with the exiton diffusion length.