Nebulizer spray pyrolysis Sm3+ doped TiO2 thin film characteristics and room temperature gas sensing

Abstract

In this work, pure TiO2 and Samarium doped (1, 3, 5 wt%) TiO2 thin films was successfully deposited on the FTO substrate by Nebulizer spray pyrolysis technique. The result suggested prepared TiO2 film have tetragonal structure and an anatase phase along the (101) direction. According to the UV–Vis-NIR spectroscopic analysis, all the deposited films exhibited a high optical percentage of transmittance, surpassing 80 % in the visible region. The FESEM observation indicated that the TiO2 surface morphology is highly sensitive to the increasing of dopant concentration. The FTIR spectroscopic results confirmed the presence of functional chemical bonding in the deposited films, as evidenced by the reflectance spectra. The ethanol sensing properties of 3 % Sm doped TiO2 films found to exhibit rapid response time at 32 s and a recovery at 20 s for 200 ppm at room temperature for 200 ppm concentration. Moreover, 3 % Sm doped TiO2 thin film electrical resistance, which was measured at 0.6 × 106 O, decreased significantly compared to other materials, indicating enhanced gas sensing properties.

Keywords

• Bandgap
• Optical properties
• Spray pyrolysis
• Sensors
• TiO2