Effect of CsxWO 3 Nanoparticles Content and Atomic Ratio for Near Infrared Cut-off Characteristics
In this work, the ceramic nanocomposites films with homogeneous dispersions of tungsten bronze nanoparticles with ternary additive cesium have been prepared by mixing Urethane acrylic/UVcoating binder and dispersed sol depending on the atomic ratio and the particle contents. Furthermore, we are synthesized the CsxWO3 with different annealing at 700, 800, and 900 °C in an N2 gas for 1 hr respectively. The structure and sizes of ceramic particles was observed XRD and PSA spectrometer, the heat-shielding properties of their films were investigated by NIR spectrometer. Synthesized Cs0.33WO3 particles with annealing at 800 °C typically formed hexagonal tungsten bronze structure for good absorption of NIR, size observed as being 30-100 nm and <150 nm. Especially, remarkable absorption of NIR wavelength ranges makes ceramic composite films good candidate for use as a heat shielding window, it clearly shows useful for applications where heat shield is required.
Microstructure and electrical–optical properties of cesium tungsten oxides synthesized by solvothermal reaction followed by ammonia annealing
Cesium tungsten oxides (Cs{sub x}WO{sub 3}) were synthesized by solvothermal reactions using ethanol and 57.1 vol% ethanol aqueous solution at 200 {sup o}C for 12 h, and the effects of post annealing in ammonia atmosphere on the microstructure and electrical-optical properties were investigated. Agglomerated particles consisting of disk-like nanoparticles and nanorods of Cs{sub x}WO{sub 3} were formed in the pure ethanol and ethanol aqueous solutions, respectively. The samples retained the original morphology and crystallinity after annealing in ammonia atmosphere up to 500 {sup o}C, while a small amount of nitrogen ion were incorporated in the lattice. The as-prepared Cs{sub x}WO{sub 3} sample showed excellent near infrared (NIR) light shielding ability as well as high transparency in the visible light region. The electrical resistivity of the pressed pellets of the powders prepared in pure ethanol and 57.1 vol% ethanol aqueous solution greatly decreased after ammonia annealing at 500 {sup o}C, i.e., from 734 to 31.5 and 231 to 3.58 {Omega} cm, respectively. - Graphical abstract: Cesium tungsten oxides (Cs{sub x}WO{sub 3}) with different morphology were synthesized by solvothermal reaction, and the effects of post-ammonia annealing on the microstructure and electrical-optical properties were investigated.
Transparent and low resistive nanostructured laser ablated tungsten oxide thin films by nitrogen doping: I. Nitrogen pressure
Nitrogen incorporated tungsten oxide films are deposited on heated quartz substrates (973 K) for various nitrogen background pressures (namely, pN2 = 0.04, 0.08, 0.12, 0.17 and 0.20 mbar) by the pulsed laser deposition technique. The prepared films are characterized by using techniques such as x-ray diffraction (XRD), energy dispersive x-ray spectroscopy (EDX), atomic force microscopy (AFM), scanning electron microscopy, micro-Raman spectroscopy, UV–visible spectroscopy and temperature dependent dc electrical resistivity studies. XRD measurements revealed the presence of tungsten sub-oxide and WO3 phases depending on the nitrogen ambient pressure. Nitrogen incorporation in the films is confirmed through EDX analysis. Morphological features consisting of densely packed, void-free grains with a distinct grain boundary are portrayed through the AFM images of the films. The WO3 lattice distortion due to nitrogen incorporation is discussed using micro-Raman spectra of the films. Band gap narrowing, moderate transmittance in the visible range and the very low resistivity exhibited by the films prepared at pN2 = 0.12 mbar are imperative as far as solar cell applications are considered. A comparably higher visible transmittance with a band gap of 3.141 eV and a low resistivity obtained for the N : WO3 films prepared at a nitrogen ambient of 0.17 mbar is among the best reported for the coexistence of transparency in the visible range and conductivity in tungsten oxide films, which make them significant for micro-electronic applications.