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

[Display omitted] •Sm3+ doped TiO2 films were deposited on FTO glass substrate using nebulizer spray pyrolysis technique.•The average optical transmittance is above 90% of Sm:TiO2 films.•The optical bandgap energy of 3.49 eV was found in Sm (3 wt%):TiO2 films.•The fast response of ethanol gas sensing showed at room temperature.•Sm (3 wt%) doped TiO2 thin film with a response time of 32 s and a recovery time of 20 s; the resistance of 0.6x106 Ω falls more than that of pure TiO2. 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.