Study of the photoluminescence properties of crystal phosphors SrTiO3:Pr3+ and SrTiO3:Pr3+, Al

Abstract

Fine-grained powder crystal phosphors SrTiO 3 :Pr 3+ and SrTiO 3 :Pr 3+ , Al have been investigated. Their photoexcitation, luminescence, and photoconductivity spectra have been recorded. It is found that only one center ( ) is responsible for the luminescence in SrTiO 3 :Pr 3+ , while the luminescence in SrTiO 3 :Pr 3+ , Al is due to two centers: ( ) × and . A mechanism of energy transfer upon luminescence excitation from the ( ) × center is proposed.

Influence of La substitution on local structural and photoluminescence properties of SrTiO3:Pr phosphor

“…However, the introduction of metal cations of different valences into the SrTiO 3 matrix can enhance the emission via a number of mechanisms. For example, lattice defects created by Al 3+ incorporation can absorb the excitation radiation, acting as sensitizers, and transfer it to the Pr 3+ ions, resulting in their characteristic red emission [8].Moreover, the doping of SrTiO 3 : Pr 3+ powders with divalent metal ions (Mg 2+ and Zn 2+ ) forms impurity energy levels near the bottom of the conduction band that provide more efficient energy transfer from the matrix to the Pr 3+ ions [8,9]. Furthermore, replacement of Sr with a pair of Li + and Na + ions is believed to facilitate the formation of hole traps, increasing the probability of recombination of electrons with captured holes, thus raising the luminescence intensity [9].…”

“…For example, lattice defects created by Al 3+ incorporation can absorb the excitation radiation, acting as sensitizers, and transfer it to the Pr 3+ ions, resulting in their characteristic red emission [8].Moreover, the doping of SrTiO 3 : Pr 3+ powders with divalent metal ions (Mg 2+ and Zn 2+ ) forms impurity energy levels near the bottom of the conduction band that provide more efficient energy transfer from the matrix to the Pr 3+ ions [8,9]. Furthermore, replacement of Sr with a pair of Li + and Na + ions is believed to facilitate the formation of hole traps, increasing the probability of recombination of electrons with captured holes, thus raising the luminescence intensity [9]. Enhancement of luminescence is also observed as a result of the introduction of trivalent metal ions, such as Al 3+ , Ga 3+ and In 3+ , substituting for Ti 4+ , explained by the compensation for the Pr 3+ charge in the site of Sr 2+ ions and the higher degree of crystallinity [8,9].…”

“…Furthermore, replacement of Sr with a pair of Li + and Na + ions is believed to facilitate the formation of hole traps, increasing the probability of recombination of electrons with captured holes, thus raising the luminescence intensity [9]. Enhancement of luminescence is also observed as a result of the introduction of trivalent metal ions, such as Al 3+ , Ga 3+ and In 3+ , substituting for Ti 4+ , explained by the compensation for the Pr 3+ charge in the site of Sr 2+ ions and the higher degree of crystallinity [8,9]. Substitutions of monovalent cations for Sr 2+ and trivalent cations for Ti 4+ are used in order to achieve charge compensation.…”