Self-reduction process of Eu3+ to Eu2+ in Eu-doped SrLaMgTaO6 double perovskite thin films and its photoluminescence properties

Abstract

This paper describes the novel fabrication of Eu 3+ -doped SrLaMgTaO 6 (SLMTOE) thin films on a SrTiO 3 (100) substrate using pulsed laser deposition (PLD) and an investigation of the dependence of their structural and photoluminescence (PL) properties on the partial pressure of oxygen. SLMTOE red phosphor has been vigorously studied in recent years because of its high efficiency compared to that of commercial red phosphor. However, the PL properties of thin films of this phosphor have not yet been reported. Our results indicate that SLMTOE grown at 100 mTorr produces the brightest red emission. A study of this sample also showed that the PL intensity at low partial pressure (10–100 mTorr) differed from that at high partial pressure (100–200 mTorr). X-ray photoelectron spectroscopy (XPS) analysis indicated that the enhanced PL intensity at low partial pressures is associated with defects in the thin film lattice, and the weakened PL intensity at high partial pressures can be related to the change in the ratio of Eu 3+ to Eu 2+ as a consequence of self-reduction. Our XPS result implies that the change of A site doped with Eu 3+ ion is correlated significantly with the PL properties of double-perovskite thin films. • Eu 3+ -doped SrLaMgTaO 6 thin films were fabricated on a SrTiO 3 (100) substrate. • The PL properties of SLMTOE films depend on the partial pressure of oxygen. • Strong photoluminescence observed at low partial pressures because of film defects. • At higher oxygen partial pressure, the Eu 3+ ions were reduced to Eu 2+ ions.