Study On Preparation And Application Of Transparent Conductive Tin Based Oxide Nanoparticles

Sb doped SnO2 (antimony doped tin oxide, ATO) nanoparticles are a new and prospective transparent conductive material. The material has broad application prospects such as electromagnetic shielding, electrochromism, energy-saving glass, display, lithium ion batteries, solar cells, conductive and antistatic materials. The particle size, structure, composition and aggregation degree of ATO nanoparticles have important impacts on the optical and electrical properties of the powder and then the application effect of the powder. It is very important to make a fundamental study on the control mechanism of the preparation conditions on the crystal structure and performance. In addition, to improve the performance of the ATO nanoparticles, new approaches should be developed.The main contents of this paper are summarized as follows:1. The metal Sn grains were dissolved by HCl, HNO3 and mixed acid of HCl and HNO3, respectively. The dissolution time of the metal Sn grains was compared in different conditions including the acid type and acid quantity. The result of the study suggested that HNO3 acted mainly as the dissolution agent and HCl acted mainly as the inhibition agent of the hydrolysis of Sn(NO3)4 forming into H2SnO3 precipitate. The cooperation of HCl and HNO3 shortened the dissolution time of the metal Sn grains significantly. SnO2 nanoparticles were prepared starting from the dissolved metals used by the three different acids. The effects of the preparation process on the structure, morphology and particle size of the ATO nanoparticles were investigated. Results indicated that SnO2 nanoparticles prepared from the Sn solution which was obtained from the mixed acid and metal Sn grains had spherical shape, smaller particle size, good dispersibility and crystallinity. An improvement in degree of crystallinity was observed as the calcination temperature increased. The addition of PVA as a dispersing agent during the process of preparing SnO2 nanoparticles can reduce the powder particle size and increase the dispersibility of the ATO nanoparticles.2. Sb2O4 powders were prepared and the effect of the calcination temperature on the structure and morphology of Sb2O4 powders was investigated. The results showed that the precursor possessed the orthorhombic Sb2O3 crystal structure and can be transformed intoα-Sb204 at 400-600℃, but there was still a small amount of the orthorhombic Sb2O3. The orthorhombic Sb2O3 can transform intoα-Sb2O4 completely at 800℃. Also, it was found that the volatile phenomenon of Sb occurred in the temperature exceeding 400℃, and the Sb atomic percentage at the surface increased. When the temperature exceeded 700℃, the volatility phenomenon of Sb was not obvious.3. ATO nanopowders with low resistivity and high dispersibility were synthesized. The effects of Sb doping concentration, pH value, Sn ion concentration, reaction temperature, dispersing agents, drying and calcination temperature on the structure and properties of ATO nanoparticles were investigated. The results showed that the average particle size, crystallinity and the pellet resistivity decreased but n(Sb+)/n(Sb+) increased with increasing Sb doping concentration. Also, the pellet resistivity decreased with decreasing the pH value. When the content of PVA and PEG dispersant was 6% and 4%, respectively, the comprehensive property factor of the powders reached the minimum. ATO nanoparticles were found to have better dispersibility when the precursor was packed to dry compared with that being dried directly in air.4. ATO nanoparticles can be used as conductive, antistatic materials and have application in the field of transparent conductive electrodes, especially. ATO conductive slurry and ATO transparent conductive coatings have been prepared. The effects of the dispersant and Sb doping concentration on the performance of the ATO conductive slurry and ATO transparent conductive coatings have been investigated. Results on the ATO slurry study showed that the combined effect of the oleic acid and PVP can increase the stability of the slurry. Also, the stability of the slurry can be increased with increasing the Sb doping concentration. The slurry was found to have the best stability when the content of oleic acid, PVP, ATO powder and ethanol was 1%,1%,9% and 89%. Results on the ATO coating study showed that the crystallinity, resistivity and transmittance of the ATO coating decreased, the band gap decreased initially and then increased slightly with increasing the Sb doping concentration.