科研之友
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摘要
The molecular structures and absorption spectra of three tetrahydroquinoline dyes (C2-1, C1-1, and C1-5) with a tetrahydroquinoline moiety as the electron donor, a cyanoacrylic acid moiety as the electron acceptor, and different thiophene-containing electron spacers were investigated by density functional theory (DFT) and time-dependent DFT (TD-DFT). The calculated geometries indicate that a strong conjugation is formed in the dyes and the conjugate length increases with the increase of spacer length. The interfacial charge transfer between the semiconductor electrode and the tetrahydroquinoline dyes are electron-injection processes from the excited dyes to the semiconductor conduction band. The simulated absorption bands are assigned to pi-pi* transitions, which exhibit appreciable red-shift with respect to the experimental bands owing to the lack of direct solute solvent interaction and the inherent approximations in TD-DFT. Moreover, the effect of different spacers on the molecular structures, absorption spectra, and photovoltaic performance were comparatively discussed.
