TY - BOOK
T1 - Defect, Phase, and Interface Engineering of Titanium Dioxide Thin Films Grown by Atomic Layer Deposition for Solar Fuel Production
AU - Saari, Jesse
PY - 2022
Y1 - 2022
N2 - Constantly growing need for energy is causing inevitable problems that the humankind must solve in the near future. Global energy consumption is rising due to population and economic growth, and burning of fossil fuels, such as oil, coal, and natural gas, is accounted for global warming. Therefore, supplying this massive energy demand by using sustainable and carbon-neutral energy sources at the expense of fossil fuel power sector is needed. Solar power is one of the most promising sustainable energy technologies. However, due to challenges caused by diurnal cycle and intermittency of sunlight, development of solar energy storage technologies is highly important. Photoelectrochemical technology aims at storing solar energy into chemical form, i.e., solar fuels by splitting water molecules to hydrogen and oxygen or driving reduction of water and carbon dioxide to methanol, methane or other hydrocarbons and their derivatives. Despite great progress, photoelectrodes in photoelectrochemical solar fuel reactors still lack the required efficiency and stability for commercial viability. This Thesis provides insights into atomic-level structure, charge carrier dynamics, and crystallization of TiO2 thin films grown by atomic layer deposition, and their performance as photoelectrode coatings. The results show that mass densities, precursor traces, and oxide defects of amorphous TiO2 can be varied in a desirable way by the atomic layer deposition growth temperature when using tetrakis(dimethylamido)titanium(IV) and H2O precursors at 100–200 °C. The growth temperature of 100 °C results in TiO2 with low mass density and precursor traces that inhibit crystallization up to 375 °C and stabilize the anatase phase. TiO2 grown at 200 °C, instead, exhibits high concentration of oxide defects and distinctly higher mass density facilitating electrical conductivity and direct crystallization into rutile at an exceptionally low post deposition annealing temperature of 250 °C. The photoelectrochemical analysis for TiO2/Si photoelectrodes revealed that crystallization is necessary to achieve desired chemical stability, and the lower the crystallization temperature the thinner the interfacial SiO2 layer and the better the photocurrent onset potential. The results of this Thesis on TiO2 thin films grown by atomic layer deposition are applicable to tailoring of protective photoelectrode coatings for economically viable photoelectrochemical solar fuel production.
AB - Constantly growing need for energy is causing inevitable problems that the humankind must solve in the near future. Global energy consumption is rising due to population and economic growth, and burning of fossil fuels, such as oil, coal, and natural gas, is accounted for global warming. Therefore, supplying this massive energy demand by using sustainable and carbon-neutral energy sources at the expense of fossil fuel power sector is needed. Solar power is one of the most promising sustainable energy technologies. However, due to challenges caused by diurnal cycle and intermittency of sunlight, development of solar energy storage technologies is highly important. Photoelectrochemical technology aims at storing solar energy into chemical form, i.e., solar fuels by splitting water molecules to hydrogen and oxygen or driving reduction of water and carbon dioxide to methanol, methane or other hydrocarbons and their derivatives. Despite great progress, photoelectrodes in photoelectrochemical solar fuel reactors still lack the required efficiency and stability for commercial viability. This Thesis provides insights into atomic-level structure, charge carrier dynamics, and crystallization of TiO2 thin films grown by atomic layer deposition, and their performance as photoelectrode coatings. The results show that mass densities, precursor traces, and oxide defects of amorphous TiO2 can be varied in a desirable way by the atomic layer deposition growth temperature when using tetrakis(dimethylamido)titanium(IV) and H2O precursors at 100–200 °C. The growth temperature of 100 °C results in TiO2 with low mass density and precursor traces that inhibit crystallization up to 375 °C and stabilize the anatase phase. TiO2 grown at 200 °C, instead, exhibits high concentration of oxide defects and distinctly higher mass density facilitating electrical conductivity and direct crystallization into rutile at an exceptionally low post deposition annealing temperature of 250 °C. The photoelectrochemical analysis for TiO2/Si photoelectrodes revealed that crystallization is necessary to achieve desired chemical stability, and the lower the crystallization temperature the thinner the interfacial SiO2 layer and the better the photocurrent onset potential. The results of this Thesis on TiO2 thin films grown by atomic layer deposition are applicable to tailoring of protective photoelectrode coatings for economically viable photoelectrochemical solar fuel production.
M3 - Doctoral thesis
SN - 978-952-03-2686-9
T3 - Tampere University Dissertations - Tampereen yliopiston väitöskirjat
BT - Defect, Phase, and Interface Engineering of Titanium Dioxide Thin Films Grown by Atomic Layer Deposition for Solar Fuel Production
PB - Tampere University
CY - Tampere
ER -
