Synthesis and physical properties of Fe doped La₂O₃ thin films grown by spray pyrolysis for photocatalytic applications

Abstract

This paper deals with synthesis and physical investigation of iron doped Lanthanum oxide thin films (La2O3: Fe). These films are grown on glass substrates at 460 °C by spray pyrolysis with different molar ratios of Fe to La, varying from 0 to 5%. X-ray diffraction analysis shows that undoped La2O3 thin film crystallizes under a mixture of hexagonal and cubic structures. SEM images reveal porous and fuzzy network of nanocrystalline La2O3. AFM images confirm the granular and nanocristalline structure of these films. The principal Raman peak owed to La–O vibration mode at 340 cm−1, confirms the formation of lanthanum oxide La2O3. For iron- doped films, FTIR spectroscopy reveals not only the La–O vibration mode at 457 cm−1 but also a peak at 1394 cm−1 which is related to the ternary LaFeO3. Photoluminescence spectra show that iron doping reduces radiative recombination. Thereby, doped samples can be used for photocatalysis experiment with methylene blue (MB). After 120 min exposure to solar light, a noticeably photodegradation of MB is obtained with 4% Fe doped La2O3. This work shows that Fe doped La2O3 is a promising material for various sensitive applications such as gas detection and bio-sensors.