Effect of variation of precursor concentration on structural, microstructural, optical and gas sensing properties of nanocrystalline TiO2 thin films prepared by spray pyrolysis techniques

Abstract

The objective of the present paper is to investigate the effect of variation of precursor concentration (0•01, 0•02 and 0•03 M) on the structural, microstructural, optical and gas sensing properties of TiO 2 thin films. Titanium dioxide (TiO 2) films were prepared from aqueous solution of titanium chloride (TiCl 3 •6H 2 O, 99•9% pure, Merck made, Germany) onto the glass substrates heated at a temperature of 350 • C by the spray pyrolysis technique. Bandgap energy of the films vary from 3•28 to 3•29 eV. X-ray diffraction shows that films to be nanocrystalline with anatase phase having tetragonal crystal structure. The d values calculated from electron diffraction patterns (TEM) were observed to be matching with d values calculated from XRD. Transmission electron microscopy (TEM) reveled that grain sizes were observed to increase (10-29 nm) with an increase in the concentration of precursor solution. The gas sensing performance of the films was tested. Keywords. Spray pyrolysis; nanocrystalline TiO 2 ; electron diffraction pattern.

Influence of precursor solution concentration on the structural, optical and humidity sensing properties of spray-deposited TiO2thin films

“…Thus, the formation of a thin film with porous anatase phase with maximum surface area can enhance the humidity-and gas-sensing properties of TiO 2 -based sensors. For the last two decades, TiO 2 thin film based humidity sensors have been extensively studied because of their hydrophilic properties [13,14] . In the literature, there are many reports on thick-film TiO 2 humidity sensors, but fewer works on TiO 2 thin film based humidity sensors have been reported, even though TiO 2 thin films show lower response and recovery time than thick-film sensors.…”

Enhancing Structural Integrity, Optical Properties, and Room Temperature Formaldehyde Sensing Through Optimized Spray Deposition Rates

“…Consequently, when the TiO 2 thinfilm surface interacts with formaldehyde gas, its conductivity increases due to an elevated electron concentration. 45 Selectivity.-TiO 2 film sensors deposited at different rates were tested for their gas sensing responses to formaldehyde, toluene, ethanol, xylene, and butanol. The sensors showed excellent selectivity towards formaldehyde due to small-scale crystallites and its lower dissociation energy 46 compared to other tested gases, shown in Fig.…”

Humidity sensing properties of spray deposited Fe doped TiO2 thin film

“…The increase in microstrain can sizably reduce the crystallite size and enhance surface area of the films. The increase in specific surface area can then improve the surface activity of the Fe-doped TiO 2 thin film [29,30] . Improvement in surface activity of synthesis materials can affect the photocatalytic as well as sensing properties of the material.…”