Doping induced enhancement for acetone sensing in ceria

Ceria is a wide bandgap semiconductor oxide, however, by introducing oxygen vacancies (V_o), the electronic structure of ceria can be precisely tuned, resulting in a narrowed band gap and improved charge transport. Doping with lower-valent cations introduces V_o to maintain charge neutrality, thereby imparting robust chemiresistive and semiconducting properties. These vacancies act as active sites for analyte adsorption and are crucial for enhancing sensing performance. In this study, samaria-doped ceria was synthesized using a modified co-precipitation method. Structural analysis such as XRD, Raman spectroscopy, and HR-TEM confirm the formation of cubic fluorite-type structure in all samples. PL and UV-Vis spectroscopy show the enhanced defect levels with increase in Sm doping. XPS validated the presence of Vₒ and the oxidation states of Ce⁴⁺ and Sm³⁺. I-V characterization confirmed the ohmic conductance behaviour, while chemiresistive measurements show selectivity and sensitivity towards acetone. Additionally, kinetic parameters were extracted via Langmuir-Hinshelwood modeling, confirms the importance of oxygen vacancies in acetone sensing. Additionally, DFT based calculation shows that Sm-doping in ceria modulates its electronic structure by Fermi level shifting towards conduction band causing substantial availability of electrons inducing the formation of V_o.