Use this URL to cite or link to this record in EThOS: https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.756341
Title: Particle size, morphology, phase transition and energy efficient applications of hydrothermally produced VO2(D)
Author: Teixeira Gomez, Diana C.
ISNI:       0000 0004 7429 294X
Awarding Body: UCL (University College London)
Current Institution: University College London (University of London)
Date of Award: 2018
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Abstract:
Thin films of thermochromic vanadium(IV) oxide, VO2(M), were synthesized using sol-gel/spin coating techniques and aerosol assisted chemical vapour deposition (AACVD). The effect of precursor solution aging, thickness and annealing temperature was studied. A recently reported vanadium dioxide phase, VO2(D), was studied in this work. Its structure (reported in the literature) is discussed and another possible structure is presented and analyzed in this work. VO2(D) nanoparticles of 20-30 nm were synthesized for the first time using vanadium pentoxide as a precursor via hydrothermal synthesis. The phase transition from VO2(D) to thermochromic VO2(M) was studied and reported to be the lowest phase transition temperature (165 °C) in order to obtain thermochromic VO2. The pH conditions of the starting solution were studied and reported to be a critical and important feature in the reaction. Different morphologies of VO2(D) microparticles were prepared using ammonium metavanadate as a precursor by hydrothermal synthesis. VO2(D) microparticles from 1 to 5 micron in size were reported with star shape, round-ball, elongated particles shape among others at different pH. The effect of the starting pH solution in the final product was studied. Thermochromic VO2(M) microparticles were obtained after mild calcination. Finally, thermochromic polymeric films were prepared using VO2(M) nanoparticles obtained after low temperature calcination of VO2(D) nanoparticles. The nanoparticles were encapsulated into a polyvinylpyrrolidone matrix and deposited via spin coating onto a glass substrate.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.756341  DOI: Not available
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