Synthesis And Properties Of Novel Titanium Oxo Clusters (TOSs)

Dye-sensitized solar cells have attracted great interest during the past decade in theconversion of sunlight to electricity due to their low cost and high efficiency. In terms ofatomic structure and chemical activity, titanium-oxo-clusters are bridges connectingpractice and theory in the mode of the dye sensitized TiO2nanomaterials. It has wideapplication in photocatalysis, gas sensing and the decomposition of toxic organicpollutants. The clusters synthesized by the solvent thermal method with novel structuresand unique properties have drew great attention. This work is devoted to studying thesolvothermal method to prepare novel titanium-oxo-clusters, and characterizing theirstructures and optical properties. The major studies of this work are as follows:In introduction, the research progresses in metal oxygen clusters are reviewedbriefly; crystal structures and recent development of Ti-O clusters are describedspecifically.In chapter2, under solvothermal condition, two metal-phen functionalizedcompounds,[Ti17O28(OiPr)16(Cophen)2](1) and [Tii17O28(OPr)18(Cdphen)2](2) aresuccessfully prepared and crystallized. The structures of the compounds are bestdescribed as an oxo-isopropanoxo Ti17parent fused with two M-phen moieties. Theband structure of the cluster is modified by the coordination of the metal complex andthe absorption of the material is improved. Moreover, the Co-phen decorated Ti17clustercan be utilized as the precursor to prepare organo hybrid TiO film using a simplenon-template coating method, and the films have unique microstructures of perfecthollow spheres, bowls, and doughnuts. Effect photocurrent response is observed for theCo-phen modified film. The Co-phen moiety plays an important role in electrontransition. The results demonstrate the unique application of TOCs in both theoreticaland practical aspects.In chapter3, we select9-anthracenecarboxylate (9-AC) as a photoactive ligand,and two compounds [Ti6O6(OiPr)6(9-AC)](3) and [Ti6O4(OiPr)6(cat)4(9-AC)2](4) are obtained by solvothermal reactions. Their crystal structures, fluorescence andphotocurrent response properties are characterized. Solvent induced fluorescencechange is observed. The fluorescence of the cluster solution can be off by irradiationand on by oxygen oxidation. It is found that9-AC is a good photosensitizer that caneffectively increases the photoelectric conversion of the TiO materials.In chapter4, under solvothermal condition, eight crystals with dicarboxylic acidand catechol are first synthesized and their structures are characterized. They appearunique red color. The clusters are used as the precursor to prepare organo hybrid TiOfilm by a simple coating method, and the films show unique microstructures.Photoelectric properties of the catechol modified titanium-oxo-clusters are examined.