The adsorption of tetrazole derivatives at the surface of TiO2 anatase for dye-sensitized solar cell application: a periodic density functional theory study

Dye-sensitized solar cells (DSSCs), which have been considered as one of the most promising and low-cost alternatives to conventional inorganic silicon-based solar cells, have attracted considerable attention since reported by O Regan and Grätzel in the 1990‘s [1-3].In this work, we have selected four typical additives, 2H-tetrazole (2HTz), 2H-tetrazole-5-thiol (5TTz), 2H-tetrazole-5-amine (5ATz) and TBA, to investigate their interaction modes and mechanisms with TiO2anatase (101), (100) and (001) surfaces in both vacuum and acetonitrile conditions by a periodic DFT method. The results are analyzed by means of adsorption modes and energies, band structures, total and partial density of states (TDOS and PDOS). We find that the additive adsorption can strongly affect the geometric and electronic structures of three different TiO2 surfaces. Moreover, the solvent environment and the adsorption density of additive molecules are also important and influential to the structural, energetic and electronic properties of additive-anatase systems so as to influence the conversion efficiency of DSSC. Table 1 shown key adsorption and electronic structure parameters of both bare and additive sensitized TiO2anatase (101) surfaces with and without solvent condition.