Structural, Electronic and Optical Properties of Nd-Doped Anatase TiO₂ for Dye-Sensitized Solar Cells from Density Functional Theory

Abstract

The structural, electronic and optical properties of pure and neodymium (Nd) doped anatase titanium dioxide (TiO2)are investigated via first-principles calculations within density functional theory (DFT) approach. The band gap reduces to ~0.398 eV when Ti4+ is substituted with Nd3+ in TiO2 crystal structure. The presence of Nd 4f states in the conduction band of TiO2 clarifies the reducing of the band gap. The dielectric constant and refractive index of Nd-doped TiO2 increase compare to pure TiO2. Nd-doped TiO2 able to enhance light absorption to longer wavelength spectrum. The first-principles results obtained satisfy the criteria for Nd-doped TiO2 to become feasible photoanode material in dye-sensitized solar cell (DSSC) device.

Defect engineered (Er3+/Nd3+) codoped TiO2 photoanodes for enhanced photoelectrochemical and photovoltaic applications

“…The bandgap of TiO 2 is observed to be slightly reduced from 2.26 eV to 2.22 eV in the presence of Nd (0.4 mol%) doping, similar changes were found elsewhere, 10 which can be attributed to the redshift of the conduction band. 66 Here, Nd 3+ introduced the 4f–4f intra-band transitions between the TiO 2 bandgap, and these energy states are spread beneath the conduction band and also extend into the deep level, as illustrated in the schematic diagram in Fig. 5.…”