Samarium-doped ceria nanostructured thin films grown on FTO glass by electrodepostion

Abstract

Electrical, optical or catalytic properties of ceria can be tuned via doping by rare earth elements. The innate properties of ceria-based materials can be further amplified by using nanostructured ceria. In this study, Sm-doped ceria (SDC) coatings were grown on the FTO glass substrate by means of cathodic deposition. Films were obtained from mixed Sm3+/Ce3+ aqueous nitrate solutions, applying -0.8V/(SCE) potential for 1 h. Selected conditions gave rise to adherent, homogeneous and well-covering nanostructured SDC thin films. EDX analysis showed that 0.8 and 1.5 mol% Sm3+ led to 3.4 and 6.3 at.% Sm in the SDC films. XRD and Raman analysis confirmed the formation of cubic fluorite-type CeO2. However, Sm-doping decreased the crystallite size of nanostructured ceria. The effect of annealing on SDC film was also studied. An improvement in crystallite quality was found with increasing temperature. Optical absorption properties were studied and the band gap value (Eg) of 3.07 eV was determined for pure ceria. Sm-doped ceria exhibited a red shifting. The Eg values were 2.97 and 2.81 eV, in due order.