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Enhancing Electron Injection in Dye‐Sensitized Solar Cells by Adopting W 6+ ‐Doped TiO 2 Nanowires: A Theoretical Study
Author(s) -
Hao Li,
Wang Jian,
Bai FuQuan,
Xie Mo,
Zhang HongXing
Publication year - 2015
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201500813
Subject(s) - doping , dopant , chemistry , dye sensitized solar cell , homo/lumo , nanowire , titanium dioxide , nanotechnology , materials science , optoelectronics , molecule , organic chemistry , electrode , electrolyte , metallurgy
As a donor type dopant in titanium dioxide, W 6+ was found to move the conduction band (CB) edge of TiO 2 downward and also to influence the electron‐injection process in dye‐sensitized solar cells (DSSCs). To investigate the electron‐injection capabilities of DSSCs and to optimize their efficiency by W 6+ doping, the geometry and electronic properties of both free and adsorbed TiO 2 nanowires were investigated on the basis of extensive density functional theory calculations. A four‐layer (TiO 2 ) 12 nanowire with 12 possible doping sites was set up, and the effect of W 6+ in different positions was analyzed. The results indicate that in the W 6+ ‐doped (TiO 2 ) 12 systems, the Ti–O W (O W = oxygen atom that is connected to the W atom) bonds are longer than the corresponding Ti–O bonds in (TiO 2 ) 12 . The CB edge is significantly influenced by the doping position. The CB energy level moves upward gradually as doped W 6+ moves deep into (TiO 2 ) 12 . For all adsorbed catechol/(TiO 2 ) 12 systems with the W 6+ dopant, the LUMO maps are distributed over the layer in which W 6+ is doped. The W 6+ doping position plays a crucial role in the electron‐injection and electron‐transport process in DSSCs. Therefore, different positions of W 6+ doping in TiO 2 would be a feasible strategy to control and improve semiconductor materials to obtain DSSCs with more efficient electron injection.