Host excitation-induced red emission from Pr3+ in strontium barium niobate thin film

Optical quality SrxBa1−xNb2O6 (SBN) thin films doped with Pr3+ ions were successfully grown on fused quartz substrates using a pulsed laser deposition technique. Both as-grown and annealed samples were studied at either room temperature or at 10 K. Luminescence measurements show that most 4f2→4f2 emissions from Pr3+ centers were efficiently quenched in the films. Strong red emission from 1D2 to 3H4 at ∼610 nm accompanied by weak emission to other 3Hj multiplets could be observed only by UV excitation into the SBN conduction band. At 10 K, the main emission peak splits into four components. In addition, a broadband SBN-host luminescence was identified at ∼560 nm in the annealed sample, associated with the charge-transfer vibronic exciton. As an interstitial ion, Pr3+ may occupy a 15-, 12-, 9- or 6-fold cage surrounded by oxygen and was found to occupy all four possible sites in SBN thin films. This behavior is different from Eu3+- SBN where Eu3+ only occupies a 6-fold site.