An unusual thiazolo[5,4-d]thiazole sensitizer for dye-sensitized solar cells

Photostable Voltage-Sensitive Dyes Based on Simple, Solvatofluorochromic, Asymmetric Thiazolothiazoles

A family of asymmetric thiazolo[5,4-d]thiazole (TTz) fluorescent dye sensors has been developed, and their photophysical sensing properties are reported. The π-conjugated, TTz-bridged compounds are synthesized via a single-step, double condensation/oxidation of dithiooxamide and two different aromatic aldehydes: one with strong electron-donating characteristics and one with strong electron-accepting characteristics. The four reported dyes include electron-donating moieties (N,N-dibutylaniline and N,N-diphenylaniline) matched with three different electron-accepting moieties (pyridine, benzoic acid, and carboxaldehyde). The asymmetric TTz derivatives exhibit strong solvatofluorochromism with Stokes shifts between 0.269 and 0.750 eV (2270 and 6050 cm^-1) and transition dipole moments (Δμ = 13-18 D) that are among the highest reported for push-pull dyes. Fluorescence quantum yields are as high as 0.93 in nonpolar solvents, and the fluorescence lifetimes (τ_F) vary from 1.50 to 3.01 ns depending on the solvent polarity. In addition, thermofluorochromic studies and spectrophotometric acid titrations were performed and indicate the possibility of using these dyes as temperature and/or acid sensors. In vitro cell studies indicate good cell membrane localization, negligible cytotoxicity, promising voltage sensitivities, and photostabilities that are 4 times higher than comparable dyes. Their ease of synthesis and purification, remarkable photophysical properties, and chemically sensitive TTz π-bridge make these asymmetric dye derivatives attractive for environmental and biological sensing or similar molecular optoelectronic applications.

Low-band gap and fluorescent poly(triphenylamine-thiazolo[5,4-d]thiazole) copolymer dye

The synthesis, characterization and spectroscopy of a new fluorescent poly(triphenylamine-thiazolo[5,4-d]thiazole) dye with low band gap energy have been reported.

Thiazolo[5,4-d]thiazole-based organic sensitizers with strong visible light absorption for transparent, efficient and stable dye-sensitized solar cells

Five thiazolothiazole-based dyes, bearing electronrich ProDOT groups, were used as sensitizers in thin-layer DSSCs (active area: 0.25–3.6 cm²; TiO₂ thickness: 3.0–6.5 μm), giving efficiencies up to 7.71% coupled with excellent stability over 1000 h.

Direct arylation as a versatile tool towards thiazolo[5,4-d]thiazole-based semiconducting materials

A variety of thiazolo[5,4-d]thiazole-based organic optoelectronic materials is synthesizedviaa straightforward Pd-catalyzed C–H arylation protocol.