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Abstract: A series of organic dyes with a donor–acceptor–acceptor (D–A–A) configuration, in which various diarylthienylamine donors and a cyanoacrylic acid acceptor are bridged by a low-band-gap 2,1,3-benzothiadiazole acceptor, have been synthesized, characterized, and employed as photosensitizers for dye-sensitized solar cells (DSSCs). The adoption of 2,1,3-benzothiadiazole as the bridging acceptor endowed these tailor-made dyes with superior light-harvesting capabilities in comparison to their previously reported pyrimidine-based analogs. After fine-tuning the fabrication conditions, DSSCs based on these dyes showed solar spectral responses extending to the near-IR region and achieved power conversion efficiencies (PCEs) of up to 3.16% (OHexDPTB) under simulated AM 1.5G irradiation (100 mW cm−2). [Copyright &y& Elsevier]

Abstract: The D–π–A organic dyes which feature diphenylthienylamines as the donors and cyanoacrylic acid as the acceptors, are carefully examined. Comprehensive spectral response analysis and transient techniques are exploited to investigate the effects of various functionalized π-bridge and hexyloxy side chains in donor moieties on carrier injection efficiencies, electron diffusion length and dye-regeneration efficiencies. Retarded charge recombination of /electrolytes+ is found in molecules with the hexyloxy chains and diphenyl-substituted dithienosilole groups. However, regeneration rate is revealed as being slower with the larger sensitizer structure and the higher HOMO levels. A clear trade-off between charge recombination and dye regeneration is found and should be taken into account in future molecular designs of D–π–A dyes. [Copyright &y& Elsevier]

An amine-free oligothiophene-based dye (BTB) featuring a tailor-made dianchoring function, a spiro-configured central unit, and bulky end-capping TIPS groups to diminish intermolecular interactions and to suppress aggregation-induced self-quenching was synthesized to achieve efficient dye-sensitized solar cells with a high power conversion efficiency of 6.52%. [ABSTRACT FROM AUTHOR]