DFT and TD‐DFT Study on Azobenzene‐Based Dye Covalently Attached to Silane Coupling Agents: Toward Dye‐Sensitized TiO₂ Catalyst and Dye‐Sensitized Solar Cell Applications

Abstract

Herein, density functional theory (DFT) and time-dependent DFT (TD-DFT) studies of 4-[(4-methoxyphenyl)diazenyl] naphthalen-1-amine (MPDNA) covalently attached to a silane coupling agent (SCA) (namely, 4-(triethoxysilyl)butane-1,2-epoxide (OTES)) with a terminal oxirane group (MPDNA-OTES) were performed to determine the influence of SCAs on the geometry of photosensitizing dyes with multiple photoisomers or conformers. CHÀ O interaction between the hydroxyl group, which was formed by an epoxy ring-opening reaction between MPDNA and OTES, and the 1-naphthylamine moiety resulted in two conformers of MPDNA-OTES. The dominant trans-isomer conformation of MPDNA-OTES indicates a high driving force of electron injection (À 1.61 eV) and significantly contributes to the photocurrent in dye-sensitized TiO 2 catalysts and dyesensitized solar cells. It is concluded that by combining OTES and a photosensitizing dye containing a 1-naphthylamine moiety, the CHÀ O interaction can be utilized to regulate the geometry of the dye to realize characteristics favorable for electron injection into the conduction band of TiO 2 .

Flexible Nano-TiO2 Sheets Exhibiting Excellent Photocatalytic and Photovoltaic Properties by Controlled Silane Functionalization─Exploring the New Prospects of Wastewater Treatment and Flexible DSSCs

“…One of those research articles reports the photocatalytic activity of TiO 2 surface modified with 3-aminopropyltriethoxysilane (APTES) in degrading the methylene blue (MB) dye to an extent of 88% after 240 min of light irradiation. In another report, the role of adsorption and calcination in the photocatalytic degradation of the MB dye in the presence of APTES modified TiO 2 was investigated, in which a maximum of 96% degradation percentage after 240 min of irradiation was reported. , Takeshita has carried out computational studies at the density functional theory (DFT) and time-dependent-DFT levels on an azobenzene-based dye covalently attached to silane coupling agents (SCAs). The SCAs were coupled to a terminal oxirane group of the photosensitizing dye containing a 1-naphthylamine moiety, and it was found that the CH–O interactions can be utilized to regulate the geometry of the dye to achieve characteristics favorable for electron injection into the conduction band of TiO 2 .…”