Dithienosilole Based Organic Sensitizers for Efficient Dye-Sensitized Solar Cells

Abstract

Recently, organic sensitizers-based dye sensitized solar cells (DSSCs) have attracted much attention due to their several advantages such as low cost preparation, structural diversity, and high power conversion efficiency (η: 8-9%). Organic sensitizers consist typically of three segments of donor, π-linker, and acceptor (D-π-A), which are shown to have efficient intramolecular charge transfer (ICT) characteristics. Particularly, organic sensitizers bearing dithienosilole (DTS) as a π-linker have shown to have high efficiencies (η: 7.6-10.5%) in DSSCs performance due to its unique photophysical properties (σ-π conjugation) and coplanarity. In addition, the efficiency in DSSC performance is a quite sensitive depending on the nature of substituents at 3position of DTS ring. For examples, the bulky substitution on silicon atom of DTS ring may reduce the π-π stacking interactions of dyes and may be beneficial to high electron injection yield and the power conversion efficiency. These facts prompted us to develop new organic dyes containing DTS π-linker and investigate the effect of bulky substituent at 3-position of DTS ring in DSSC performance. Herein, we report the results of our investigation on the preparation, photophysical properties, electrochemical behavior, and DSSC performance of two novel DTS dyes.