Publication detail

Structural and optical evolution in CeO2 films induced by aluminum doping: A comprehensive study

BAGCIVAN, A. AKTAS, S. YILDIRIM, Y. POLAT, Ö. SOBOLA, D. SEN, C. CAGLAR, Y. CAGLAR, M.

Original Title

Type

journal article in Web of Science

Language

English

Original Abstract

This study investigates the impact of aluminum (Al) doping and oxygen vacancies on the structural, electronic, and optical properties of Cerium Oxide (CeO₂) films. The films were fabricated on glass substrates using the sol-gel spin coating method for both undoped and Al doped CeO₂. Theoretical insights from the DFT + U + V method further explore how Al doping and oxygen vacancies influence the electronic structure and optical behavior of ceria. Experimentally, Al doping was found to increase the lattice parameters and reduce the crystallite size without forming secondary phases. Raman spectroscopy revealed a shift to lower wavenumbers in Al-doped samples, while XPS analysis confirmed the presence of both Ce³⁺ and Ce⁴⁺ oxidation states, along with Al³⁺ and O2⁻ ions. Optical measurements showed a decrease in the optical band gap from 3.14 eV to 2.93 eV as the Al concentration increased to 5 %. Additionally, the optical dielectric constant slightly decreased, whereas optical conductivity improved with the incorporation of aluminum. Theoretical calculations show that oxygen vacancies were shown to reduce the band gap by introducing localized Ce³⁺ mid-gap states, while Al doping led to a gradual narrowing of the band gap without creating new states within it. The combination of Al doping and oxygen vacancies resulted in both further band gap narrowing and the appearance of mid-gap states. Optical property calculations revealed that both oxygen vacancies and Al doping reduced the intensity of the dielectric functions at 310 nm. Moreover, these two factors had opposing effects on the electron energy loss spectrum (EELS) at low energies: Al doping induced high-intensity peaks, while oxygen vacancies diminished these peaks.

Keywords

CeO2; Sol-gel; Al doping; DFT+U+V method; Oxygen vacancies

Authors

BAGCIVAN, A.; AKTAS, S.; YILDIRIM, Y.; POLAT, Ö.; SOBOLA, D.; SEN, C.; CAGLAR, Y.; CAGLAR, M.

Released

31. 1. 2025

Publisher

ELSEVIER

ISBN

0272-8842

Periodical

Ceramics International

Year of study

Number

State

United Kingdom of Great Britain and Northern Ireland

Pages from

2846

Pages to

2860

Pages count

URL

https://www.sciencedirect.com/science/article/pii/S0272884224053604?dgcid=author

BibTex

@article{BUT193390,
  author="Aybike {Bagcivan} and Seda {Aktas} and Yucel {Yildirim} and Özgür {Polat} and Dinara {Sobola} and Cengiz {Sen} and Yasemin {Caglar} and Mujdat {Caglar}",
  title="Structural and optical evolution in CeO2 films induced by aluminum doping: A comprehensive study",
  journal="Ceramics International",
  year="2025",
  volume="51",
  number="3",
  pages="2846--2860",
  doi="10.1016/j.ceramint.2024.11.262",
  issn="0272-8842",
  url="https://www.sciencedirect.com/science/article/pii/S0272884224053604?dgcid=author"
}