Cu掺杂量对Zn-Cu共掺TiO2薄膜光学带隙的影响

Effect of Cu doping amount on optical band gap of Zn-Cu Co-doped TiO thin film

采用溶胶-凝胶旋涂法,分别以钛酸四丁酯(Ti(OC4H9)4)为钛源、硝酸锌(Zn(NO3)2·6H2O)为锌源、硝酸铜(Cu(NO3)2·3H2O)为铜源制备了不同掺杂量的Zn、Cu共掺TiO2薄膜。分别采用X射线衍射仪(XRD)、薄膜测厚仪、紫外-可见分光光度计(UV-Vis)对所制备的样品进行表征。结果表明:与本征TiO2和2.0 at%Zn^2+-TiO2相比,Cu^2+的掺杂减小了样品的晶面间距及晶粒尺寸、增加了样品的半高宽及比表面积,进而提高了薄膜的光催化活性能。随着Cu2+掺杂量的增加,样品沿(101)晶面择优取向先增强后减弱,薄膜的吸光度呈现先升高后降低的趋势,TiO2的带隙值由3.424 eV减小到3.325 eV。与本征TiO2和2.0 at%Zn^2+-TiO2相比,2.0at%Zn^2+-1.0 at%Cu^2+-TiO2的样品结晶度最好,(101)晶面择优取向最佳,薄膜表面的缺陷较少、较为均匀平整且吸光度更好,光学带隙值最小为3.325 eV。

TiO2 thin films with different doping amount of Zn and Cu were prepared by sol-gel spin coating method and used Ti(OC4H9)4 as the titanium source,Zn(NO3)2·6 H2O as the zinc source,and Cu(NO3)2·3 H2O as the copper source,respectively.The samples were characterized by X-ray diffractometer(XRD),film thickness gauge and Ultraviolet visible spectrophotometer(UV-Vis).The results show that compared with the intrinsic TiO2 and 2.0 at%Zn^2+-TiO2,the doping of Cu2+reduces the crystal surface spacing and grain size of the samples,increases the half width and specific surface area of the samples,and improves the photocatalytic activity of the films.With the increase of Cu^2+doping concentration,the preferred orientation of the sample along the(101)crystal surface first increases and then weakens,the absorbance of the film first increases and then decreases,and the band gap value of TiO2 decreases from 3.424 eV to 3.325 eV.Compared with the intrinsic TiO2 and 2.0 at%Zn^2+-TiO2,the crystallinity of 2.0 at%Zn^2+-1.0 at%Cu^2+-TiO2 is the best,(101)the preferred orientation of the crystal surface is the best,the defects on the film surface are less,the film surface is flatter,and the absorbance is better,and the minimum optical band gap value is 3.325 eV.