立方相WO3薄膜的制备及表征

Preparation and Characterization of Cubic WO_3 Films

以偏钨酸铵(NH_4)_6W_4O_(24)·6H_2o为钨源,聚乙二醇(PEG)为配位聚合物,采用聚合物前驱体法制备了立方晶相WO_3(c-WO_3)薄膜,利用X射线衍射、扫描电镜、能谱分析及高分辨透射电镜等手段对结构进行了表征,并考察了煅烧温度、溶液pH值及镀膜衬底对WO_3薄膜晶体结构与形貌的影响.结果表明,以FTO导电玻璃为衬底,450℃热处理3 h的样品为c-WO_3,薄膜光滑平整,均匀良好,表面颗粒粒径为60 nm,厚度为2.9μm,晶体生长有序度较高;热处理温度在400～550℃和不同pH值条件下制得的薄膜均为立方晶体结构;样品的颗粒粒径随前驱体溶胶pH值升高而减小;以石英玻璃和石墨衬底镀膜得到的样品均为单斜晶体结构,表明衬底对WO_3薄膜晶体结构具有明显的影响.

Cubic WO3 films were prepared by the polymeric precursor method using ammonium metatungstate as precursor and polyethylene glycol as structure-directing agent. The obtained materials were characterized by means of X-ray diffraction （XRD）, scanning electron microscope （SEM）, energy disperse spectroscope （EDS） and high-resolution transmission electron microscope （HRTEM）. The influence of calcination temperature, pH value and substrates on the structure and morphology of films was investigated. The results indicate that the surface morphology of the resulting film on FTO glass has particle of 60 nm in size as cubic WO3 calcined at 450℃, and the films are smooth and glossy with an uniform thickness of 2.9 μm. The structures of all samples on FTO glass annealed at 450-550℃ or prepared at the different pH values are cubic WO3. The particle size of the films decreases with the increase of the pH values. Monoclinic WO3 is formed when the films are prepared on quartz glass and graphite substrate, indicating that the substrates have apparent influence on the crystal structure of WOs thin films.