Impedance Spectroscopic Inspection Toward Sensitivity Enhancement of Ag-Doped WO₃ Nanofiber-Based Carbon Monoxide Gas Sensor

Abstract

This work reports the impedance analysis and carbon monoxide gas sensing response of tungsten oxide (WO3) nanofibers with silver (Ag) nanoparticle doping. The Ag-doped WO3 nanofibers were prepared by an electrospinning technique. The impedance spectroscopic measurements of undoped and Ag-doped WO3 nanofibers were performed to study the contribution of electrical parameters involved in the electron transport. The impedance modeling obtained from the fitted Nyquist plot shows that the RC components attributed to Ag-WO3 interface are introduced to the system upon Ag addition. Carbon monoxide (CO) gas detection was carried out by resistance measurement using a DC method. The sensitivity of Ag-doped WO3 nanofibers is found to be greater than that of the undoped sample. The improved sensitivity is derived from the high interface resistance between Ag and WO3 grains. The contribution of Ag dopants is conceived to induce electronic structure alteration of the sensor material.

Effect of silver doping on the band gap tuning of tungsten oxide thin films for optoelectronic applications

“…Due to interfacial energy, two-dimensional growth is preferred between WO 3 and other oxide substrates, leading to high-quality films at reduced temperatures. Sol-gel, electro-spinning, hydrothermal, thermal evaporation, microwave irradiation, spray pyrolysis, sputtering, and electron beam evaporation techniques have been used to prepare WO 3 thin films [ [14] , [15] , [16] ]. There are benefits and drawbacks to every approach.…”

Optical Absorption and Photoconversion Characteristics of WO₃ Nanofiber Photoanodes Prepared by Electrospinning with Different Calcination Temperatures

“…Photoelectrochemical (PEC) water splitting using metal oxide semiconductor electrodes is a versatile technique employed for hydrogen production via photoelectrolysis of water [1][2][3]. Tungsten oxide (WO3) is an n-type metal oxide semiconductor employed in various applications such as photocatalysis [4], electrochromism [5], and gas sensing [6,7] due to its functional optical and electronic properties. The theoretical maximum photoconversion efficiency of WO3 photoanode obtained under AM 1.5G irradiation at 100 mW/cm 2 is expected to be 4.8% [8].…”