Photoluminescence of Sm³⁺ doped ZrO<inf>2</inf> coatings formed by plasma electrolytic oxidation of zirconium

Abstract

In this paper, we have investigated photoluminescence (PL) of Sm3+ doped ZrO2 coatings formed by plasma electrolytic oxidation (PEO) of zirconium in electrolyte containing Sm2O3 powder. Obtained PL emission spectra feature two distinct regions. The first region is related to ZrO2 PL band with maximum positioned at about 490 nm, while the second region in the orange-red part of the spectrum shows four sharp emission bands which are related to f-f transitions of Sm3+ from excited level 4G5/2 to the lover levels 6HJ (J=5/2, 7/2, 9/2, and 11/2). Increase of PL with time is related to increase of oxygen vacancy defects and the content of Sm3+ in the coatings formed during the process.