Electronic structures and optical properties of Ce-doped anatase TiO2 with oxygen vacancy

Shi-Wen Zhou; Ping Peng; Wen-Qin Chen; Ming-Huai Yu; Hui Guo; Zhen Yuan

doi:10.7498/aps.68.20181946

Journals >Acta Physica Sinica >Volume 68 >Issue 3 >Page 037101-1 > Article

Acta Physica Sinica
Vol. 68, Issue 3, 037101-1 (2019)

Electronic structures and optical properties of Ce-doped anatase TiO₂ with oxygen vacancy

Shi-Wen Zhou^1、*, Ping Peng^2、*, Wen-Qin Chen¹, Ming-Huai Yu¹, Hui Guo¹, and Zhen Yuan¹

Author Affiliations

¹College of Materials and Chemical Engineering, Hainan University, Haikou 570228, China

²College of Materials Science and Engineering, Hunan University, Changsha 410082, China

show less

DOI: 10.7498/aps.68.20181946 Cite this Article

Shi-Wen Zhou, Ping Peng, Wen-Qin Chen, Ming-Huai Yu, Hui Guo, Zhen Yuan. Electronic structures and optical properties of Ce-doped anatase TiO₂ with oxygen vacancy [J]. Acta Physica Sinica, 2019, 68(3): 037101-1 Copy Citation Text

show less

The 2 × 2 × 1 supercell structure of various supercell models (the red, grey and blue balls represent O, Ti and Ce atoms, respectively; the imaginary red circle shows the position of oxygen vacancy): (a) Pure anatase TiO2; (b) Ce-TiO2; (c) OV-TiO2; (d) Ce/OV-TiO2.2 × 2 × 1的超胞结构图(红色球为O, 灰色球为Ti, 蓝色球表示Ce原子的掺杂位置, 红色虚圆圈表示OV的位置) (a) Pure TiO2; (b) Ce-TiO2; (c) OV-TiO2; (d) Ce/OV-TiO2

Fig. 1. The 2 × 2 × 1 supercell structure of various supercell models (the red, grey and blue balls represent O, Ti and Ce atoms, respectively; the imaginary red circle shows the position of oxygen vacancy): (a) Pure anatase TiO₂; (b) Ce-TiO₂; (c) O_V-TiO₂; (d) Ce/O_V-TiO₂. 2 × 2 × 1的超胞结构图(红色球为O, 灰色球为Ti, 蓝色球表示Ce原子的掺杂位置, 红色虚圆圈表示O_V的位置)　(a) Pure TiO₂; (b) Ce-TiO₂; (c) O_V-TiO₂; (d) Ce/O_V-TiO₂

Download full size | View in the Article

Band structure of anatase TiO2 before and after doping (the dashed lines represent the Fermi level, EF): (a) Pure TiO2; (b) Ce-doped TiO2; (c) OV-TiO2; (d) Ce/OV-TiO2.纯TiO2和Ce/OV掺杂TiO2的能带结构图(图中虚线代表费米能级EF) (a) Pure TiO2; (b) Ce-TiO2; (c) OV-TiO2; (d) Ce/OV-TiO2

Fig. 2. Band structure of anatase TiO₂ before and after doping (the dashed lines represent the Fermi level, E_F): (a) Pure TiO₂; (b) Ce-doped TiO₂; (c) O_V-TiO₂; (d) Ce/O_V-TiO₂. 纯TiO₂和Ce/O_V掺杂TiO₂的能带结构图(图中虚线代表费米能级E_F)　(a) Pure TiO₂; (b) Ce-TiO₂; (c) O_V-TiO₂; (d) Ce/O_V-TiO₂

Download full size | View in the Article

Fig. 3. Comparison of partial density of states of anatase TiO₂ before and after doping (the dashed lines represent the Fermi level, E_F): (a) Pure TiO₂; (b) Ce-doped TiO₂; (c) O_V-TiO₂; (d) Ce/O_V-TiO₂. 纯TiO₂和Ce/O_V掺杂TiO₂的态密度图(图中虚线代表费米能级E_F)　(a) Pure TiO₂; (b) Ce-TiO₂; (c) O_V-TiO₂; (d) Ce/O_V-TiO₂

Download full size | View in the Article

Fig. 4. Calculated band energy positions of pure TiO₂, Ce-TiO₂, O_V-TiO₂, Ce/O_V-TiO₂ (the energy scale is indicated by the normal hydrogen electrode in electron volts as a reference; the short thick lines and fine red lines represent the band energy positions of TiO₂ by neglecting and considering the impurity levels, respectively). Ce/O_V掺杂锐钛矿相TiO₂的能带带边位置示意图(图中各带边位置的电位均以NHE的电位为参考零点, 粗黑线代表忽略杂质能级时的带边位置, 细红线代表考虑杂质能级时的带边位置)

Download full size | View in the Article

Fig. 5. Absorption spectra of pure and different doping TiO₂ models (inset is the expanded absorption spectra in the visible region). Ce/O_V掺杂锐钛矿TiO₂的光吸收谱(插图为可见光区光吸收谱的放大图)

Download full size | View in the Article

参量	GGA	GGA + U	LDA	LDA + U	Experiment	Theory	Error%
注: d_ap, d_eq分别表示Ti—O长键和短键的键长; 误差指LDA + U方法相对于实验值的误差.
a/nm	0.3791	0.3897	0.3745	0.3806	0.3785^[26]	0.3831^[29]	0.5548
b/nm	0.3791	0.3897	0.3745	0.3806	0.3785^[26]	0.3831^[29]	0.5548
c/nm	0.9805	0.9925	0.9447	0.9674	0.9514^[26]	0.9631^[29]	1.6817
c/a	2.5860	2.5470	2.5230	2.5410	2.5140^[26]	2.5140^[29]	1.0739
u	0.2050	0.2050	0.2080	0.2070	—	0.2050^[29]	—
d_ap/nm	0.2011	0.2031	0.1966	0.2005	0.1980^[27]	0.1973^[29]	1.2626
d_eq/nm	0.1946	0.2000	0.1914	0.1948	0.1934^[28]	0.1930^[29]	0.7238
E_g/eV	2.18	3.18	2.16	3.12	3.32^[24]	3.23^[29]	—

Table 1.

Lattice parameters and band gap width of pure anatase TiO₂ calculated at the GGA, GGA + U, LDA and LDA + U levels of theory.

采用GGA, GGA + U, LDA及LDA + U方法计算得到的纯锐钛矿相TiO₂的晶格参数和带隙宽度

参量	Ce-TiO₂			O_V-TiO₂	Ce/O_V-TiO₂
参量	This work	Experiment	Other theory	This work	This work
注: d_ap, d_eq分别表示Ce-TiO₂, Ce/O_V-TiO₂中Ce—O长键和短键的键长, 对于O_V-TiO₂则表示Ti—O长键和短键的平均键长.
a/nm	0.3822	0.3789^[25]	0.3980^[31]	0.3789	0.3827
b/nm	0.3833	—	0.3980^[31]	0.3793	0.3798
c/nm	0.9956	0.9509^[25]	0.9757^[31]	0.9824	1.0090
d_ap/nm	0.2225	—	0.2273^[32]	0.2012	0.2233
d_eq/nm	0.2183	—	0.2119^[32]	0.1946	0.2252

Table 2.

Lattice parameters of Ce/O_V single and co-doped anatase TiO₂ after the structure relaxation.

Ce/O_V单(共)掺杂锐钛矿相TiO₂弛豫后的晶胞参数

Model	E_f/eV		q/e			p/Debye
Model	Ti-rich	O-rich	O	Ti	Ce	p/Debye
Pure TiO₂	—	—	−0.720	1.440	—	0.0000
Ce-TiO₂	10.42	1.16	−0.719	1.405	1.920	0.0168
O_V-TiO₂	1.02	5.65	−0.727	1.412	—	0.0668
Ce/O_V-TiO₂	−15.84	−20.48	−0.725	1.373	1.920	0.0251

Table 3.

Defect formation energy, average net charges and average dipole moment of Ce/O_V doped TiO₂ supercell after the structure relaxation.

Ce/O_V掺杂锐钛矿相TiO₂的缺陷形成能(E_f)、平均净电荷(q)和平均偶极矩(p)

Download Citation

Save the article for my favorites

Paper Information