Effect of oxygen vacancies on the red emission of SrTiO3:Pr3+ phosphor films

The red emission of the Pr3+ ions was very sensitive to the oxygen vacancies in the host of 300-nm-thick SrTiO3 films. Comparing with the air-annealed films, a significant enhancement of up to 400% was observed in the red photoluminescence intensity for the vacuum-annealed samples, and the valence state of the Pr ions was found to be changed little. Based on the fact of the obvious overlap between the excitation band of the Pr3+ ions and emission band of the oxygen vacancies, it was suggested that the oxygen vacancies act as a sensitizer for the effective energy transfer from SrTiO3 host to Pr3+ ions. This study demonstrated that the red emission from Pr3+ ions in SrTiO3 was closely related to the oxygen vacancies.