Effect of cerium doping on the structural, optical and photocatalytic properties of SnO2 thin films prepared by spray pyrolysis method

Abstract

In the present work, we have studied the effect of Ce doping on the physical properties of Ce-doped SnO2 thin films obtained by spray pyrolysis on heated glass substrates at 480 °C during 3 min as time deposition. Specific parameters were used to prepare the chemical solution. The structural, optical and electrical properties as well as photocatalytic behavior of Ce-doped SnO2 thin films under different Ce concentrations (0–10 wt%) were investigated. XRD patterns reveal that undoped and Ce-doped SnO2 thin films are polycrystalline with both tetragonal and cubic phases, except the thin film doped at 4 wt% presents a predominant cubic structure with preferential orientation along [111] axis. The crystallite size was affected by Ce doping and was found in the range from 35.64 to 63.12 nm. The surface morphology of films examined by atomic force microscopy (AFM) shows a texture of grains and a weak roughest (4.74 nm) for the 2 wt% Ce-doped film. The average optical transmittance of the fabricated thin films was higher than 78% in the visible range and the estimated band gap energy reached 3.99 eV. Figure of merit of Ce-doped SnO2 has a maximum value of 3.87 Ω−1 at 550 nm. The highest photocatalytic degradation (19.10%) of methylene blue under UV irradiation and 100 min of exposure time is reached for the 2 wt% Ce-doped SnO2 thin film with a surface of 3.75 cm2.