ItemArticle

Tuning WO3 film properties for electrochromic applications via annealing and oxygen pressure

Title
Tuning WO3 film properties for electrochromic applications via annealing and oxygen pressure
Creator
Prabhu, Smitha G.; Kumar, Kilari Naveen; Kamath, Kavitha; Veera Pandi, N.; Nithyashree, S.; Jafri, R.Imran
Description
The objective of this investigation was to examine the intricate relationship between annealing temperature and oxygen partial pressure (PaO2) in regard to morphological, structural, and electrochemical properties of tungsten trioxide (WO3) films that were produced through sputtering. The films were deposited under two different PaO2 values, specifically 0.3 mTorr and 0.5 mTorr, and then underwent annealing at various temperatures: room temperature, 100, 200, 300, and 400 degrees Celsius. X-ray diffraction (XRD) analysis revealed a temperature-dependent transition from an amorphous to a crystalline phase. Morphological analyses conducted with scanning electron microscopy (SEM) indicated a trend towards a smoother surface as both the annealing temperature and PaO2 rose. At 400 C, the films exhibited a granular surface finish. Significantly, the film fabricated at 0.3 mTorr and subjected to room temperature (RT) annealing showed cracks, indicating inherent stress in the film. Electrochemical evaluations revealed that the WO3 film deposited at 0.5 mTorr and annealed later at 200 C demonstrated enhanced redox performance, better diffusion of ions, and remarkable reversibility. Impressive results were demonstrated in optical studies, attaining 83 % optical modulation, colouration efficiency (CE) up to 30.54 cm/C, and swift switching durations of 1.17 s for colouration and 0.82 s for decolouration. Moreover, cycling tests showed negligible degradation after 100 cycles for the films deposited at 0.5 mTorr PaO2 and treated at 200 C, emphasizing their resilience. This study furnishes a comprehensive knowledge of the consequences of annealing temperature and PaO2 collectively on WO3 films, highlighting the novel strategy of enhancing electrochromic efficacy by modifying temperature and meticulously balancing the PaO2, thus contributing to the progress of energy-efficient smart materials. 2025
Source
Optik;Volume;336;Issue;;Article No.;172439;
Date
01-01-2025
Publisher
Elsevier GmbH
Subject
Annealing; Electrochromic; Oxygen partial pressure; Sputtering; WO3
Coverage
Prabhu S.G., Department of Electronics and Communication Engineering, Nitte Meenakshi Institute of Technology, Bengaluru, 560064, India; Kumar K.N., Department of Physics, Nitte Meenakshi Institute of Technology, Bengaluru, 560064, India, Centre for Nanomaterials and MEMS, Nitte Meenakshi Institute of Technology, Bengaluru, 560064, India; Kamath K., Department of Physics, Nitte Meenakshi Institute of Technology, Bengaluru, 560064, India; Veera Pandi N., CeNSE, Indian Institute of Science, Karnataka, Bengaluru, India; Nithyashree S., Department of Electronics and Communication Engineering, Ambedkar Institute of Technology, Karnataka, Bengaluru, India; Jafri R.I., Department of Physics and Electronics, Christ University, Karnataka, Bengaluru, India
Rights
Restricted Access; Hardcopy may be available in the library
Relation
ISSN: 304026;
Format
online
Language
English
Type
Article

Citation

Prabhu, Smitha G.; Kumar, Kilari Naveen; Kamath, Kavitha; Veera Pandi, N.; Nithyashree, S.; Jafri, R.Imran, “Tuning WO3 film properties for electrochromic applications via annealing and oxygen pressure,” CHRIST (Deemed To Be University) Institutional Repository, accessed June 18, 2026, https://archives.christuniversity.in/items/show/22304.

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