Formation of nanoscale tungsten oxide structures and colouration characteristics

Bulletin of materials science

Vijay Bhooshan Kumar¹  Dambarudhar Mohanta¹ 

[1] Nanoscience Laboratory, Department of Physics, Tezpur University, Tezpur 784 028, India$$Nanoscience Laboratory, Department of Physics, Tezpur University, Tezpur 784 028, IndiaNanoscience Laboratory, Department of Physics, Tezpur University, Tezpur 784 028, India$$

关键词: Tungsten oxide;    nanoparticles;    photochromic;    thermochromic.;   

DOI  :  

学科分类：材料工程

来源: Indian Academy of Sciences

【 摘 要 】

In this work, pH dependent evolution of tungsten oxide (WO₃) nanostructures is being reported along with physical characteristics. The synthesis was carried out via an inexpensive solvothermal cum chemical reduction route, with sodium tungstate (Na₂WO₄) and cetyl trimethyl ammonium bromide (C₁₉H₄₂NBr) as main reactants. The X-ray diffraction, together with transmission electron microscopic studies have revealed formation of regular polyhedral nanocrystalline structures and fractals as one goes from higher pH (= 5.5) to lower pH (= 2) values. The average crystallite size, as calculated throughWilliamsonâ€�?�Hall plots, was varied within 2.8â€�??6.8 nm for different pH samples. Fourier transform infrared spectroscopy reveals in-plane bending vibration ð›�? (Wâ€�?�OH), observable at ∼1630 cm^-1 and strong stretching 𝜈 (Wâ€�?�Oâ€�?�W) located at ∼814 cm^-1. Raman spectroscopy has divulged WO₃ Raman active optical phonon modes positioned at ∼717 and 805 cm^-1. The thermochromic and photochromic properties of the nanoscale WO₃ sample prepared at pH = 5.5, are also highlighted.

【 授权许可】

Unknown