Oxygen Vacancy-Related Cathodoluminescence Quenching and Polarons in CeO2

Thanveer Thajudheen; Alex G Dixon; Sandra Gardonio; Iztok Arčon; Matjaz Valant

doi:10.1021/acs.jpcc.0c04631

Oxygen Vacancy-Related Cathodoluminescence Quenching and Polarons in CeO₂

J Phys Chem C Nanomater Interfaces. 2020 Sep 17;124(37):19929-19936. doi: 10.1021/acs.jpcc.0c04631. Epub 2020 Aug 18.

Authors

Thanveer Thajudheen¹, Alex G Dixon², Sandra Gardonio¹, Iztok Arčon^{3

4}, Matjaz Valant^{1

5}

Affiliations

¹ Materials Research Laboratory, University of Nova Gorica, Vipavska 11c, 5270 Ajdovščina, Slovenia.
² Laboratory of Organic Matter Physics, University of Nova Gorica, Vipavska 11c, 5270 Ajdovščina, Slovenia.
³ Laboratory of Quantum Optics, University of Nova Gorica, Vipavska 13, SI-5000 Nova Gorica, Slovenia.
⁴ Department of Low and Medium Energy Physics, J. Stefan Institute, Jamova 39, POB 000, SI-1001 Ljubljana, Slovenia.
⁵ Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, 610054 Chengdu, China.

Abstract

We used cathodoluminescence (CL) spectroscopy to characterize the oxygen vacancies (V_O) in ceria (CeO₂). The effects of the processing atmosphere and thermal quenching temperature on the nature and distribution of the intrinsic defects and on the spectroscopic behavior were investigated. The presence of polarons and associates of the polarons with the oxygen vacancies such as (V_O ^••-Ce_Ce ^')^• is demonstrated. CL intensity quenching above a critical concentration of V_O has been shown. Even though the emission centers in all samples are the same, their concentration changes with the oxygen partial pressure of the processing atmosphere. Deconvolution of the observed CL spectra shows that the emissions originating from the F⁰ centers prevail over those of F⁺ centers of V_O when the defect concentration is high.