Exploration of optoelectronic and photosensitization properties of triphenylamine-based organic dye on TiO2 surfaces.

Donor–bridge–acceptor (D–π–A) compounds have garnered significant attention, and have led to increased efficiency of photovoltaic devices. In this study, an effective D–π–A dye (TPA-PT) was designed that contains tri-phenyl-amine, thiophene-pyrimidine and cyanoacetic acid as donor (D), π-bridge and acceptor (A), respectively. The TPA-PT was adsorbed on the semiconductor surfaces, i.e., Ti₃O₆H and Ti₆O₁₂H clusters, and light was shed on the adsorption behavior by bidentate bridging @Ti₃O₆H and chelating @Ti₆O₁₂H modes. The frontier molecular orbitals (FMOs) and structural and optical properties are studied by applying density functional theory (DFT) and time-dependent DFT (TD-DFT). Important parameters including charge transfer mechanism, electronic coupling constants (|V_RP|), band alignment, electron injection (ΔG^inject), relative electron injection (ΔG_r^inject) and light-harvesting efficiency are comprehensively investigated. The charge transfer from TPA-PT dye to the semiconductor surface of Ti₃O₆H and Ti₆O₁₂H clusters is explored as well. Additionally, the computed values of open-circuit photo-voltage (V_oc) are presented for two cases of TiO₂ and PCBM. [ABSTRACT FROM AUTHOR]