The Study On Preparation And Photoelectric Properties Of Cu₂O/TiO₂ Heterostructure Thin Films

Ti O₂ is a common semiconductor materials,has the advantages of insulator and metal materials do not have,such as heat sensitivity,photoelectric properties and doping properties.Ti O₂ has great potential for application in the solar cell,photocatalytic hydrolysis,biomedical,wastewater treatment,soil purification,heavy metal removal,food industry and cosmetics industry and so on.However,the fast recombination of the photo-generated electron-hole pairs,large optical-band gap（3.2 eV for anatase and 3.0 eV for rutile）have limited the applications of TiO₂ in the solar cell.In this paper,modified TiO₂ with narrow band gap semiconductor（Cu₂O）,and study the effect of heterojunction thin films’ s morphology and structure in the photoelectric properties.The main contents are as follows:The TiO₂ nanosheets were deposited on FTO glass by hydrothermal method.The XRD results show that the pure TiO₂ nanosheets prepared by the experiment are n-type semiconductors of anatase,optical properties show that TiO₂ nanosheets have little absorption in visible light area.The photoelectrochemistry test showed that the photocurrent value is 0.048 μA/cm².We successfully fabricated high efficient Cu₂O/TiO₂ heterojunction films by simple wet chemical method.First,the effect of different preparation process on the morphology and photoelectric properties of Cu₂O/TiO₂ heterojunction films was studied.The structure and properties of Cu₂O/TiO₂ heterojunction films were studied,as C series and N series of samples,respectively.The results showed that the prepared Cu₂ O particles were Cu+,furthermore,Cu and Cu₂+ were not observed.For the sample of series C,the Cu₂ O particles size were uniform and decentralized,also had a broad-light visible absorption at 400-600 nm region,the photocurrent value is 10 μA/cm².In addition,the effects of different NaOH concentration on the morphology and photoelectric properties of heterojunction films were also studied.The results showed that the concentration of NaOH was 0.1 M,the Cu₂ O particles sizes were uniform,and the visible light absorption value was the largest.And the electrochemical workstation was used to measure photoelectrochemical properties.The results show that the photoelectrochemical properties of the films were best when the concentration of NaOH is 0.1 M,the photocurrent value is 10 μA/cm².Cu₂O nanoparticles with different morphology of Cu₂O/TiO₂ heterojunction were prepared by simple wet chemical method.The morphology of Cu₂ O nanoparticles was studied by SEM,the octahedral,cube,polyhedron and spherical Cu₂O/TiO₂ heterojunction films were prepared,respectively.Simultaneously,the growth mechanism of Cu₂ O nanoparticles with different morphology was analyzed.The UV-Vis diffuse reflectance spectra show that all the Cu₂O/TiO₂ thin films have obvious absorption on the visible light in the range of 400-600 nm.The electrochemical performance of the films is measured by electrochemical workstation.The results show that the spherical Cu₂ O of Cu₂O/TiO₂ thin film has the best photoelectron-hole efficient separation,the photocurrent value is 23 μA/cm².