Synthesis And Properties Of Rare-earth Metals Doped Titanum Oxo Clusters

Rare-earth elements have been greatly promoted the development of the materials in fluoresce, electric light source, permanent magnet, hydrogen storage, catalysts, etc.Titanium oxide materials have excellent features in the photolysis, photocatalysis, gas sensing etc. and researches in the synthesis and preparation of titanium oxide precursors and titanium oxide-related materials have received a great deal of attention. It is found that Ti O2 solar cells doped with lanthanide elements can improve the photovoltaic conversion efficiency. Inspired by the applications of lanthanide metal doped titanium oxide materials in solar cells, our recent work is aimed at exploring titanium oxo clusters combined with Ln in a unique structure. A series of titanium-lanthanide oxo clusters are synthesized and characterized. Their optical and photoelectrochemical properties are studied. The main work includes the following aspects:In introduction, the research progresses in metal oxygen clusters are reviewed briefly; crystal structures and recent development of Ti-O clusters are described specifically.In chapter 2, four rare-earth metal functionalized clusters, [Ln N2Ti11O20(OPr)17],Ln = Eu(1), Tb(2), Gd(3) and Sm(4), are synthesized under solvothermal condition.They have the same structure similar to pure Ti12 cluster. Doped by rare earth elements,fluorescence and photocurrent properties of the titanium oxide clusters are improved.In chapter 3, four rare-earth metal functionalized cluster are synthesized,[Ln2Ti10O14(Cl O4)2(Oi Pr)14(9-AC)2(CH3CN)2]·2H2O, Ln = Nd(5), Eu(6) and[Ln2Ti10O14(Cl O4)2(Oi Pr)14(bza)2(HOi Pr)2], Ln = Nd(7), Eu(8).The cluster structures of these compounds adopt a Ti10Ln2 core structure, similar to the structure of Ti12 cluster. Metal centered emission of Eu(III) is completely quenched by the coordinated 9-AC due to the lower triplet energy of the ligand. Enhanced ligandcentered fluorescence is found for the Eu(III) cluster in comparison with that of the Nd(III) analogue. A Eu-Ti O cluster to ligand energy transfer mechanism is proposed.