4th International Conference on Physical Chemistry and Functional Materials, Elazığ, Turkey, 8 - 09 April 2021, pp.115
During the last ten years, with the inconceivable presence of electronic devices in our lives, alternative solutions to battery technology have begun to be produced to supply their energy needs. As a remarkable energy harvesting technology, triboelectric nanogenerators (TENGs) have been risen to collect and convert energy from the living environment into the electricity. Based on the electrostatic induction and triboelectrification coupling working mechanism TENG provides numerous advantages such as cost-effective, energy-efficient and flexibility with material choices [1-2].
TiO2 is one of the convenient semi-conductor materials instead of using weak polymers as a friction layer in TENGs. With good chemical and mechanical stability, TiO2 films are the most widely used oxide for transparent electronic applications owing to low cost and high activity. Especially, the high-temperature phase (at 900 C), rutile exhibits enhanced surface charge density properties with varying surface modifications to interpret the TENGs performance .
TiO2 films deposited on Si(100) substrates by using the conventional RF magnetron sputtering method. To determine the behind the high-temperature crystal phase effect of the TiO2 films, structural and electrical characterizations done with X-ray diffraction, scanning electron microscopy, atomic force microscopy, semi-logarithmic current-voltage and frequency-dependent capacitance measurements.
Figure 1. As-deposited and 900 ֯C heat-treated TiO2 films a) AFM-SEM images, b) frequency dependent capacitance measurements
In Fig. 1 a) high-temperature phase causes an enormous change in the particle size of the thin film surface and increase the value from 22 to 230 nm. The variations on the surface structure under the influence of charge density caused development in the electrical properties of the thin film. In Fig. 1 b), the surface charge density characteristics received by the influence of the high-temperature phase were concerned from the frequency-dependent capacitance measurements. Consequently, 7 times higher capacitance value of the sample with heat-treatment at low frequencies was achieved. The fact that the aforementioned value is concerned at very low frequencies is regarded as a further contribution for the triboelectric, which is quite close to the natural oscillation frequency due to the triboelectric effect.
This work was supported by the Scientific and Technological Research Council of Turkey (TÜBİTAK) under the grant number of 119M972.