Title Titano anodinių plėvelių dekoravimo matomą šviesą sugeriančiais puslaidininkių nanodariniais tyrimas /
Translation of Title Study on titanium anodic films decoration with visible light absorbing semiconductor nanostructures.
Authors Kovger, Jelena
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Pages 116
Keywords [eng] nanotube ; titanium dioxide ; band gap.
Abstract [eng] New nanostructure materials, their order colonies, layered films, synthesis and construction of heterostructures allow scientists to develop at those days new or improved properties of materials that will determine the future of scientific and technological progress. The thesis is related to prospective studies of nanostructured TiO2 layers and film composites with other semiconductor nanoparticles based on their environmental friendliness, low cost, chemical and mechanical resistance. The aim of the work was the investigate the possibilities of anodic TiO2 film nanotubes for electrochemical decoration of lower band gap semiconductor nanoparticles. The methods for uniform decoration of anatase TiO2 nanotube (Ntb) films with Cu2O nanoparticles were proposed: with weakly acidic copper acetate electrolyte and alternating current. Growth of pure Cu2O crystals in the TiO2 Ntbs was based on thermodynamic analysis of the solution. It has been discovered that TiO2 Ntb films decorated with Cu2O nanoparticles are able to absorb not only the UV light, but visible light as well. By increasing amount of Cu2O deposited in the TiO2 nanotubes, the TiO2 Ntb – Cu2O absorption edge can be moved up to 2.1 eV. The possibility of electrochemical decoration of TiO2 Ntb film with semiconducting copper selenide nanoparticles in aqueous solutions and the peculiarities of the process were investigated. The effect of hydrogen doping of the Ti/TiO2 Ntb electrode for uniform decoration of TiO2 nanotubes with semiconducting nanoparticles was used for the first time. It was determined that TiO2 Ntb – Cu2O heterostructures are characterised by significantly lower dependence on the angle of incidence of excitation beam – this can be especially useful for solar cell circuits. Investigated optical properties and light absorption features of TiO2 Ntb decorated with copper selenide (Cu3Se2 and Cu2-xSe) nanoparticles. Optimized composition of hydrothermal processing solution and conditions for decoration of TiO2 Ntb film surfaces and nanotubes with nanoleafed MoS2. The uniform formation of crystalline MoS2 on the TiO2 surface is achieved with low concentration ammonium heptamolybdate and urea solutions within the temperature of 220 to 225 °C. It was determined that Ti/TiO2 Ntb – MoS2 electrodes catalyse hydrogen release from acidic solutions and the reaction is characterized by stability.
Dissertation Institution Vilniaus universitetas.
Type Doctoral thesis
Language Lithuanian
Publication date 2017