Photoluminescence properties of Pr³⁺ doped ZrO<inf>2</inf> formed by plasma electrolytic oxidation

Abstract

Pr3+ doped ZrO2 coatings were formed by the plasma electrolytic oxidation (PEO) of zirconium in electrolyte containing Pr2O3 powder. The concentration of a uniformly distributed Pr3+ in the coatings increases with time of the PEO process or the concentration of added Pr2O3 powder, causing the stabilization of the tetragonal ZrO2 at the expense of the monoclinic phase. Photoluminescence (PL) emission spectra feature two distinct regions: first attributed to the ZrO2 PL band centered at about 495 nm, while the second region with blue, green, red and NIR PL, is due to the 4f-4f transitions of Pr3+. The most intense PL emission is from 1D2→3H4 transition, however, due to the stabilization of the tetragonal ZrO2, the emissions from the 3P0,1 levels gain in PL intensity with increasing concentration of Pr3+ in the coatings.