Modassar, Hossain (2026) Conventional-Unconventional Gas Sensing and Optoelectronic Devices based on Functionalized Tungsten Oxides. PhD thesis, Jadavpur University.

Full text not available from this repository. (Request a copy)

Abstract

Tungsten (VI) Oxide (WO3) exhibits a variety of interesting applications, like electrochromic smart windows, electrochemical, photocatalytic, optoelectronic, and gas sensor devices. Magnéli phases of WO3, reduced tungsten oxides like WO2.92, WO2.9, WO2.72, WO2.62, are used in solar water splitting, photocatalysis, and optoelectronic devices due to their enhanced conductivity and stability compared to the phase pure WO3 [1, 2, 3]. The chemical phase separation observed in this compound has recently garnered significant attention. The optimal ratio of phase-separated WO3 and WO2 within this compound exhibits unusual properties, which are driven by surface-specific interactions with gas molecules. These interactions occur through insulating WO3 domains that are embedded within more insulating WO2 domains. It has been found that a chemically phase-separated system is linked to distinctive sensing behaviour towards both oxidising and reducing small gas molecules. In these compounds, a strong interplay between the surfaces and gas molecules results in a variety of sensing properties. The interactions of gas molecules with the involved phase-separated surfaces are both intriguing and complex. However, the phase-separated compositions of tungsten oxides and their potential applications remain largely unexplored. In this thesis, we examine WO3 for its optoelectronic applications, specifically focusing on the gas-sensing properties of silver (Ag) nanoparticles within a WO3 matrix. We compare the gas-sensing behaviors of this system to those of a phase-pure WO3 system. Notably, we analyse the unconventional gas-sensing properties of the phase-separated system in contrast to the conventional phase-pure WO3 system. Additionally, we perform density functional theory (DFT) calculations to investigate the adsorption configurations of NO2 molecules on the (010) surface of WO2.9 and CO molecules on the (−111) surface of WO2, calculating their corresponding adsorption energies.

Item Type:	Thesis (PhD)
Subjects:	Microstructure and Characterization
Divisions:	Nano-Structured Materials
Depositing User:	Ms Upasana Sahu
Date Deposited:	12 Nov 2026 12:06
Last Modified:	12 Nov 2026 12:06
URI:	https://cgcri.csircentral.net/id/eprint/5846

Actions (login required)

View Item