Photophysical Characteristics and Photosensitizing Abilities of Thieno[3,2-B]thiophene-based Photosensitizers for Photovoltaic and Photocatalytic Applications

Six donor−π−acceptor (D–π–A) organic dyes based on thieno[3,2-b]thiophene π-linker comprising different alkyl side chains were synthesized and characterized. Their photophysical and electrochemical properties were studied and their corresponding performances as photosensitizers (PSs) in dye-sensitized solar cells (DSSCs) and photocatalytic hydrogen production systems were also investigated. A power conversion efficiency (PCE) of 5.25 % in DSSCs and a decent H2 turnover number (TON) of 5170 (48 h) in platinized TiO2 hydrogen production system were demonstrated. The results indicated that alkyl chain engineering is one of the crucial steps in designing a superior photosensitizer.