Evaluation of structural, optical and morphological properties of La doped TiO2 nanoparticles

Abstract

The optical, structural, electrical, and gas-sensing properties of pure and lanthanum-doped TiO2:La nanoparticles are studied in this research. According to the X-ray diffraction measurements, the synthesized material grew in a tetragonal phase with (101) preferential orientation. The optical features of UV spectra reveals that all samples had high reflectance >80% in the visible area, and the band gap was determined to be between 3.49 and 3.4 eV, with an increase of up to 7.5% of La. The PL spectra reveals the strong UV emission peak that shifted marginally to a higher wavelength as the sample's doping concentration increased. The synthesized TiO2: La's size was assessed using TEM. TiO2:La nanoparticle particles may be seen in TEM pictures, and their typical crystallite size is 7 nm. The PL reveals the presence of oxygen vacancy in the produced TiO2:La sample. Thermal behaviour of the sample reveals an exothermic response with a maximum weight loss rate of 12%/min at around 400 °C, and total decomposition was determined after 50 min at a heating rate of 10 °C/min. The impedance spectroscopy research shows that resistance variations caused by grain boundaries considerably influenced the properties of the gas sensor in parameters that describes the electrochemical system's low-frequency behavior. Although the study for a precise mechanism continues, the change in impedance caused by a particular gas is commonly associated to transport mechanisms such as adsorption and charge transfer.