The improved photovoltaic performance of phenothiazine-dithienopyrrole based dyes with auxiliary acceptors

Incorporating alkyl chain decorated dithienopyrrole n-spacer with phenothiazine donor has proven to be efficient strategy for constructing novel dyes, which can achieve both large short-circuit current (J(sc)) and high open circuit voltage (V-oc) in dye-sensitized solar cells (DSSCs). To promote the light harvesting capability, auxiliary acceptors including benzotriazole (BTZ), benzothiadiazole (BTD), and quinoxaline (Qu) have been inserted into the skeleton of dyes, and much improved J(sc) have been realized. Meantime, the rational design of alkyl chains endows dyes JY53 and JY55 a good shielding effect from the penetration of electrolyte, guaranteeing a high V, (over 810 mV) through retarding unwanted interfacial charge recombination. As a result, with the assistance of introduced auxiliary acceptors and alkyl chains, the photovoltaic performance of devices have been significantly improved, and dye JY55 has achieved an excellent power conversion efficiency (PCE) of 10.06% with J(sc) of 19.18 nrA cm(-2), V-oc of 829 mV, and FF of 0.63 under AM 1.5 G irradiation.