Zn^(2+)和TiO_(2)合金化过程中不同成分占比对薄膜结构和光催化性能的影响

Effects of different compositional ratios on physical structure and optical properties of thin films during alloying of Zn2+and TiO_(2)

使用溶胶-凝胶法在单晶硅衬底上制备一批不同Zn^(2+)成分调节的TiO_(2)薄膜,观测Zn^(2+)和TiO_(2)合金化过程中光学和光催化性能的变化.X射线衍射光谱仪用于观测在合金化过程中薄膜的晶体结构变化并追踪ZnTiO_(3)化合物的形成.扫描电子显微镜、原子力显微镜用于观测合金化过程中因TiO_(2)晶格对Zn^(2+)溶解度有限而导致薄膜表面出现大量孔洞的现象.X射线光电子能谱和光学带隙用于观测Zn^(2+)与TiO_(2)合金化过程中电子结构层面的变化.最后,通过降解亚甲基蓝(MB)溶液,表明少量Zn^(2+)掺杂完全溶解在TiO_(2)中,并破坏TiO_(2)结晶质量.在Zn^(2+)的成分占比继续提高至15%的过程中,XPS峰形拟合结果验证了TiO_(2)对Zn^(2+)的溶解度有限,导致薄膜出现大量孔洞结构,薄膜的活性比表面积得以提升,同时Zn^(2+)可以有效地捕获光生e^(-)/h^(+).为了继续观察Zn^(2+)浓度对TiO_(2)的影响,将Zn^(2+)的浓度提升至40%,观察Zn^(2+)与TiO_(2)合金化过程中的现象.表明化合物ZnTiO_(3)的出现可以充当e^(-)/h^(+)的复合中心以及TiO_(2).占比的大幅下降导致合金化之后的薄膜光催化效率逐渐下降.

A batch of TiO_(2)films with different Zn^(2+)compositions are prepared on a single crystal silicon substrate by using sol-gel method to observe the changes in optical and photocatalytic properties in the alloying process of Zn^(2+)and TiO_(2).X-ray diffractometer(XRD)is used to observe the changes in the crystal structures of the films in the alloying process and to track the formation of ZnTiO_(3)compounds.Scanning electron microscope(SEM)and atomic force microscope(AFM)are used to observe the phenomena of a large number of holes on the surfaces of the films due to the limited solubility of the crystal lattice for Zn^(2+)in the alloying process.X-ray photoelectron spectroscopy(XPS)and optical bandgap are used to observe the changes at a level of the electronic structure of the films in the alloying process of Zn^(2+)with TiO_(2).Finally,by degrading the methylene blue solution,it is shown that a small amount of Zn^(2+)doping is completely dissolved in TiO_(2),destroying the TiO_(2)crystalline quality.As the compositional share of Zn^(2+)continues to increase to 15%,the limited solubility of TiO_(2)for Zn^(2+)is verified in the XPS peak fitting,resulting in a large number of hole structures in the film,and the active specific surface area of the film is enhanced,while Zn^(2+)effectively traps the photogenerated e^(-)/h^(+).In order to continue to observe the effect of Zn^(2+)concentration on TiO_(2),we increase the concentration of Zn^(2+)to 40%and observe the phenomenon in the alloying process of Zn^(2+)with TiO_(2).It is shown that the appearance of the compound ZnTiO_(3)can act as a complex center for e^(-)/h^(+)and a significant decrease in the percentage of TiO_(2)leads to a gradual decrease in the photocatalytic efficiency of the films after alloying.