Starburst configured imidazole-arylamine organic sensitizers for DSSC applications

Abstract

In this study, special consideration was given to the design and synthesis of imidazole-arylamine-based organic sensitizers with three arylamine donors (Carbazole, Triphenylamine and Phenothiazine) paired with cyanoacrylic acid acceptor to form D-D-A architecture. Phenothiazine-imidazole dye (PZIM) was found to be the best for DSSC applications in the D-D-A set. Hence, we further extended the conjugation of PZIM dye by three different spacers such as benzene (PZIMBe), thiophene (PZIMTh), and furan (PZIMFu) having different resonance energies, which resulted in the design of D-D-π-A. We have carried out the photo-physical, electrochemical, and photovoltaic performance for these six dyes. The PZIM, PZIMTh and PZIMFu dyes were identified as the efficient among the six with an average power conversion efficiency of 7.0%, 7.10% and 7.30%, respectively. Thiophene and furan outperformed benzene spacer as the best linkers in the D-D-π-A configuration. Grafting the bulky imidazole moiety onto the arylamine donor is considered to be a promising approach for tuning photovoltaic parameters by increasing the electron richness of the main electron donor core, increasing solubility, and suppressing aggregation.