Transparent conductive oxide nanocrystals : new synthesis route, characterization and applications

Abstract

Nanocomposites with dispersed inorganic nanoparticles offer functional properties not available in each individual component. For optically transparent nanocomposites, a high transmittance is required for practical applications. Thus, the nanoparticles must be uniformly dispersed in the polymer matrix with little agglomeration. In this thesis, it was achieved by a new synthesis route in which reaction induced organic encapsulated nanoparticles with high dispersibility are formed during the reaction. Using this method, we have synthesized nearly monodisperse, various shaped In₂O₃ nanocrystals from indium stearate including deltoidal icositetrahedral indium oxide which was developed for the first time. The formation mechanism of various In₂O₃ morphologies under different conditions was also investigated in detail. In addition, nearly monodisperse ~7 nm indium tin oxide (ITO) nanocrystals without any agglomerations were efficiently synthesized by pyrolysis of the indium-tin stearate precursor without using any additional organic solvents. Both TOF-SIMS and TGA measurements reveal that the ITO nanocrystals exhibit a core-shell structure which has an ITO core and a stabilizer shell. The ITO nanocrystals could not only be dispersed homogeneously in non-polar solvents forming optically clear solutions but also distributed homogeneously in PVB matrix, resulting in transparent ITO/PVB nanocomposites which show over 80% transmittance in visible light range as well as efficient NIR absorption/reflection, and have been used as interlayer for fabricating laminated glass in solar control glazing. Furthermore, ~10 nm IZO nanocrystals were synthesized via excess alcohol-assisted pyrolysis and could also be dispersed in the non-polar solvent forming optically clear solution. The hexane solution with 1 wt% IZO nanocrystals can block the 100% UV light and become an excellent UV absorber.

Date of Award	2014
Original language	English
Awarding Institution	The Hong Kong University of Science and Technology