Ti–Si–Zr TERNARY MIXED OXIDE NANOCOMPOSITE: CHEMICAL SYNTHESIS, STRUCTURAL AND OPTOELECTRONIC CHARACTERISTICS

Hailu, Habtamu 73 PAGES (19619 WORDS) Physics Thesis

Abstract:

In this work Ti-Si and Si-Ti-Zr binary and ternary mixed oxide nanocomposites were synthesized through sol-gel route. The structural and optoelectronic properties characteristics analyzed using the data generated from PL, UV-vis. and XRD spectrometry. The binary and ternary nanocomposite were synthesized with different zirconia content and calcination temperatures using Ti(OC3H7)4 (titanium(IV) propoxide) (TTIP), Si(OC2H5)4 (tetraethylorthosilicate) (TEOS), and Zr(OCH2CH2CH3)4 (zirconium(IV) Propoxide) precursors. The prepared samples were characterized using PL, XRD and UV-Vis for their structural and optoelectronic characteristics. The PL spectra analysis showed that the addition of limited amount of ZrO2 (5%) to Ti-Si binary mixed oxide retarded the recombination rate of photo-exited electron. From the XRD analysis, it was seen that adding limited amount of ZrO2, decreased the average crystallite size of the nanocomposite, and the smallest average crystal size found was 12.9 nm for Ti-Si-5%Zr calcined at 500oC. The UV-Vis analysis also confirmed that addition of ZrO2 improved the absorption band to the smallest band-gap energy, which may have resulted from quantum size effect. The bandgap energy of the prepared ternary nanocomposite varied from 2.18 eV to 2.77 eV and the smallest band-gap energy found was 2.18 eV for Ti-Si-5%Zr calcined at 500oC, whereas the prepared binary nanocomposite calcined at 300oC was 3.07 eV. The above properties obtained as the result of formation of ternary heterojunctions clued the possible application of such system for solar cell, artificial photosynthesis and photocatalytic applications