Synthesis of cyanovinyl thiophene with different acceptor containing organic dyes towards high efficient dye sensitized solar cells

A series of donor-pi-acceptor (D-pi-A) metal-free organic dyes employing a diethylamine moiety as donor, phenyl with and without cyanovinyl thiophene unit as a pi-spacer and acrylic acid, rhodanine-3-acetic acid, and benzimidazole-5-carboxylic acid as acceptor/anchor, have been designed and synthesized through simple synthetic procedures and investigated as photosensitizers for the dye-sensitized solar cell (DSSC) application. The effects of both the pi-spacer and an acceptor modification upon the optoelectronic properties, theoretical and photovoltaic properties of the dyes were studied. In general, DSSCs fabricated with the dyes containing cyanovinyl thiophene unit as a pi-spacer shows more than two times higher efficiency than the DSSCs fabricated without cyanovinyl thiophene unit. The maximum power conversion efficiency of 3.01% was achieved for the cyanovinyl thiophene unit in the pi-spacer and acrylic acid acceptor dye based DSSC. (C) 2016 Elsevier Ltd. All rights reserved.