Microstructural, optical and electrochromical properties of W-doped Nb2O5 thin films prepared by dip-coating process using sols obtained by the chloroalkoxide route
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Undoped and W-doped Nb2O5 thin films have been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and atomic force microscopy (AFM) in order to study the influence of W doping on their structural and morphological properties. The synthesized Nb2O5 thin films have been found to possess an orthorhombic crystal structure having crystallite sizes 10–31 nm. The UV–visible spectroscopy shows the optical bandgap ~ 3.60 eV. The cyclic voltammetric studies show that the colouration efficiency of the films improves upon W doping with the optimum value of 68.7 cm2/C at 600 nm for the 3 at.% W-doped film. The chronoamperometric studies reveal that the switching response of the films becomes better upon W doping. The electrochemical impedance spectroscopy (EIS) data has been analyzed by fitting it to the equivalent electrical circuit (EEC) using Nova software.
The use of XRD and UV–Vis measurement facilities at Centre for Interdisciplinary Research, MNNIT Allahabad, India, and FESEM and SPM characterization facilities at Central Instrument Facility, IIT BHU, Varanasi, India are gratefully acknowledged. Financial support provided under the project, Third phase of Technical Education Quality Improvement Programme (referred to as TEQIP-III), Ministry of Human Resource Development, Govt. of India is also appreciatively acknowledged.
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