Synthesis And Properties Of Organic-Inorganic Hybrid Titanium Oxide With Photoelectric Activity

Titanium-oxo materials have wide applications in photodegradation, photocatalysis and photoelectric conversion. Dye-sensitized solar cells(DSSCs) have attracted great interest during the past decades due to the low cost and high efficiency in the conversion of sunlight to electricity. Currently, great attention has been paid on titanium dioxide nanomaterial, which is used as making material for solar cell. The exploitation and research on titanium dioxide nanomaterial, in some way, have promoted the research and development of titanium oxo clusters(TOCs). It can be used as the precursors for preparation of nano-Ti O2, in addition, the clear structure information can also provide the basis for intensive research of titanium-oxo materials. Thus, studies on synthesis, structures and properties of TOCs are of great concern. In this paper, solvothermal method, an easy and simple handle way, and suitable functionalized organic ligands were selected to synthesize novel organic-inorganic hybrid TOCs, which can be served as the precursor for fabrication of DSSCs. Then the structures, charge transfer and photoelectric properties of the TOCs were measured. The thesis mainly includes the followings:Firstly, a brief introduction has been made on current development and applications of TOCs, then an outline of applications in DSSCs, photocatalysis and photoelectric converting were studied.In chapter 2, a new dye-coordinated compound, [Ti4(OiPr)8(PAR)4]?H2O(1), has been synthesized under solvothermal condition. In the photocurrent response performance, compound 1 is taken as a new photosensitizing dye and coated on Ti O2 electrode, and I2/I3- solution is used as electrolyte. A series of comparative experiments show that photoelectric response of the new synthetic TOC-sensitized electrode is significantly enhanced. The mainly reason is that as the titanium alkoxide hydrolysis, dye molecular is fixed and uniformly dispersed on the surface of semiconductor. This work creates a new vision on the exploration of dye sensitizer of DSSCs.In chapter 3, a series of new TOCs doped with transition metals, [Ti6O4(OiPr)10(cat)2(benz)2](2), [Ti12O12(OEt)22(cat)2(benz)4M2](M = Co, Mn, Ni, 3-5), were synthesized using solvothermal methods. Single crystal X-ray diffraction is used to analyze the structures of the compounds. The crystals are used as the precursors to prepare the organic-inorganic hybrid film electrodes with unique microstructures by coating process, then the photocurrent measurement was conducted. The photoelectric response properties can be enhanced through immersing the prepared mesoporous Ti O2 film in the solution of crystals. Meanwhile, The photoelectric properties also can be improved by doping cobalt, which illustrate these materials have potential applications in photovoltaics.In chapter 4, two novel TOCs modified with functionalized organic ligands, [Ti10O10(OiPr)12(cat)4(phen/bpy)2](6, 7), were synthesized by solvothermal methods. Studies on crystal structures of the two compounds show that 2,2’-bipyridine/1,10-phenanthroline and catechol are coordinated with Ti(IV) directly. This work has not been completed and other properties of the compounds are still being studied.