121st General Meeting of the KCS

Type Poster Presentation
Area Material Chemistry
Room No. Event Hall
Time 4월 20일 (금요일) 11:00~12:30
Code MAT.P-347
Subject Characterization of Hexagonal Tungsten Bronze CsxWO3 Nanoparticles and Their Thin Films Prepared by Chemical Coprecipitation and Wet-Coating Methods
Authors Yeong Il Kim*, Yong-Cheol Kang
Department of Chemistry, Pukyong National University, Korea
Abstract The hexagonal tungsten bronze CsxWO3 nanoparticle was synthesized by a chemical coprecipitation method of ammonium tungstate and CsCO3 in acidic condition. This synthetic method for cesium tungsten bronze is reported for the first time as far as we know. The synthesized CsxWO3 as precipitated showed a weak crystallinity of hexagonal unit cell with a crystalline size of about 4 nm without annealing. When the synthesized CsxWO3 was annealed in N2 atmosphere, the crystallinity and crystalline size systematically increased maintaining the typical hexagonal tungsten bronze structure as the annealing temperature increased. The analyzed Ce content in the bronze was about 0.3 vs W, which is very close to the theoretical maximum value, 1/3 in cesium tungsten bronze. According to XPS analysis, the reduced tungsten ions as both the forms of W5+ and W4+ existed and the contents systematically increased as the annealing temperature increased up to 800 oC. The CsxWO3 thin films on PET substrate were also prepared by a wet-coating method using the ball-milled solution of the annealed CsxWO3 nanoparticles at various temperatures. The near-infrared shielding property of these thin films increased systematically as the annealing temperature increased up to 800 oC as expected with increasing contents of reduced tungsten ions.
E-mail ykim@pknu.ac.kr