Doping induced enhancement for acetone sensing in ceria

Area of Science:

• Materials Science
• Nanotechnology
• Chemical Sensing

Background:

• Ceria (CeO2) is a wide bandgap semiconductor oxide.
• Oxygen vacancies (V_o) tune ceria's electronic structure, narrowing the band gap and improving charge transport.
• Doping with lower-valent cations, like samarium (Sm), introduces V_o for enhanced semiconducting and chemiresistive properties, crucial for sensing applications.

Purpose of the Study:

• To synthesize and characterize samaria-doped ceria for gas sensing applications.
• To investigate the role of oxygen vacancies in enhancing the sensing performance towards acetone.
• To elucidate the electronic structure modifications induced by Sm-doping using experimental and computational methods.

Main Methods:

• Modified co-precipitation method for synthesizing Sm-doped ceria.
• Structural characterization using XRD, Raman spectroscopy, and HR-TEM.
• Optical characterization (PL, UV-Vis), surface analysis (XPS), electrical measurements (I-V, chemiresistive), and DFT calculations.

Main Results:

• Formation of a cubic fluorite-type structure confirmed for all Sm-doped ceria samples.
• Increased defect levels and validated presence of V_o and Sm³⁺/Ce⁴⁺ oxidation states with increasing Sm doping.
• Selective and sensitive chemiresistive response to acetone, with kinetic parameters confirming the importance of V_o.

Conclusions:

• Sm-doping effectively tunes ceria's electronic structure, creating oxygen vacancies that enhance acetone sensing.
• The study highlights the potential of Sm-doped ceria as a sensitive material for acetone detection.
• DFT calculations confirm that Sm-doping induces V_o formation by shifting the Fermi level, crucial for improved sensing.