Pyrochlore-structured Y2Ti2O7–2TiO2 composite thin films for photovoltaic applications

Munawar, Khadija and Mansoor, Muhammad Adil and Olmstead, Marilyn M. and Yusof, Farazila and Misran, Misni and Basirun, Wan Jefrey and Mazhar, Muhammad (2019) Pyrochlore-structured Y2Ti2O7–2TiO2 composite thin films for photovoltaic applications. Journal of the Australian Ceramic Society, 55 (4). pp. 921-932. ISSN 2510-1560

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Official URL: https://doi.org/10.1007/s41779-019-00329-3

Abstract

A titanium-based heterobimetallic single-source precursor [Y2Ti4(μ3-O)4(μ2-O)3(H2O)(TFA)8(THF)5].3(THF) (1) (where TFA = trifluoroacetato and THF = tetrahydrofuran) was successfully used to fabricate pyrochlore-structured Y2Ti2O7–2TiO2 composite thin films on fluorine-doped tin oxide (FTO) substrates using the aerosol-assisted chemical vapor deposition technique (AACVD). The precursor complex (1), isolated in crystalline form by reacting yttrium (III) acetate monohydrate with titanium (IV) isopropoxide and trifluroacetic acid in THF solution, was characterized by physicochemical methods such as melting point, microanalysis, FT-IR, 1H-NMR, thermogravimetric analyses (TGA/DTG), and single-crystal X-ray diffraction. Thin films prepared at 550 °C were investigated by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), field emission gun-scanning electron microscopy (FESEM), and energy-dispersive X-ray spectroscopy (EDX) which demonstrated the development of mesoporous structured microballs of Y2Ti2O7–2TiO2 with precise stoichiometry. The optical analysis showed that Y2Ti2O7–2TiO2 has a direct optical band gap of 1.8 eV. Photo-oxidation of water via Y2Ti2O7–2TiO2 thin films was carried out under simulated solar irradiation of AM 1.5 G (100 mW cm−2) using three-electrode photoelectrochemical cell in of in three separate 0.5 M electrolyte solutions of NaOH (pH = 13.5), Na2SO4 (pH = 7.2), and citrate buffer (pH = 4). A best photocurrent density of ~ 60 μA cm−2 at + 0.8 V vs. SCE was observed at pH of 13.5. These observations were further validated by electrochemical impedance spectroscopy (EIS) studies in terms of charge transportation and its recombination time. © 2019, Australian Ceramic Society.

Item Type: Article
Uncontrolled Keywords: Aerosol-assisted chemical vapor deposition; Band gap; Single-source precursor; Thin film; Y2Ti2O7–2TiO2
Subjects: Q Science > QD Chemistry
T Technology > TJ Mechanical engineering and machinery
Divisions: Faculty of Engineering
Faculty of Science > Dept of Chemistry
Depositing User: Ms. Juhaida Abd Rahim
Date Deposited: 03 Mar 2020 07:43
Last Modified: 03 Mar 2020 07:43
URI: http://eprints.um.edu.my/id/eprint/23937

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