Electronic, Structural, and Optical Properties of Mono-Doped and Co-Doped (210) TiO2 Brookite Surfaces for Application in Dye-Sensitized Solar Cells—A First Principles Study

Abstract

Titanium dioxide (TiO2) polymorphs have recently gained a lot of attention in dye-sensitized solar cells (DSSCs). The brookite polymorph, among other TiO2 polymorphs, is now becoming the focus of research in DSSC applications, despite the difficulties in obtaining it as a pure phase experimentally. The current theoretical study used different nonmetals (C, S and N) and (C-S, C-N and S-N) as dopants and co-dopants, respectively, to investigate the effects of mono-doping and co-doping on the electronic, structural, and optical structure properties of (210) TiO2 brookite surfaces, which is the most exposed surface of brookite. The results show that due to the narrowing of the band gap and the presence of impurity levels in the band gap, all mono-doped and co-doped TiO2 brookite (210) surfaces exhibit some redshift. In particular, the C-doped, and C-N co-doped TiO2 brookite (210) surfaces exhibit better absorption in the visible region of the electromagnetic spectrum in comparison to the pure, S-doped, N-doped, C-S co-doped and N-S co-doped TiO2 brookite (210) surfaces.

Enhanced Fe-TiO2 Solar Photocatalysts on Porous Platforms for Water Purification

“…TiO 2 is a semiconductor that presents a wide band gap (~3.2 eV for anatase, ~3.0 eV for rutile and 3.4 eV for brookite [ 17 ], at room temperature) and is usually excited with high-energy UV photons, above the semiconductor’s band gap [ 18 , 19 ]. As a result, pure TiO 2 absorbs in the UV region (4–5% of the solar spectrum [ 18 ]), which makes its photocatalytic efficiency low under visible light (visible region comprehends ~45% of the solar spectrum [ 20 ]).…”

Superior efficiency of BN/Ce2O3/TiO2 nanofibers for photocatalytic hydrogen generation reactions

“…In contrast, the rutile and Ce2O3 have conduction levels that are close to the Fermi level. This sequence of the energy levels is mainly due to the redundant electronics of the anatase surface migrate to rutile and Ce2O3 [99,100]. The heterostructure of BCET2 has a different junction between valance bands and conduction bands, which leads to the formation of impurity energy levels (IELs).…”

DFT study of TiO2 brookite (210) surface doped with silver and molybdenum

“…In yet another study, researchers investigated the general trend in electronic properties of TiO 2 anatase photocatalysts co-doped with nitrogen and transition metals (Sc, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Nb, Mo, and Cd) [44]. Dima et al investigated structural, electronic, and optical properties of brookite (210) surface mono-and co-doped with N, C, and S [45]. In this work, we use the first principle calculations to investigate the visible light sensitization of brookite TiO 2 monodoped and co-doped with 4d transition metals silver and molybdenum.…”