Investigation of luminescent properties inherent to SrTiO₃:Pr³⁺ luminophor with Al impurity

Abstract

The red-emitting SrTiO₃:Pr³⁺,Al luminophors that can be used for the white light emitting diodes (LEDs) were prepared using the sol-gel method. The starting materials were SrCl₂, Ti (O – i – C₃H₇)₄, Al(NO₃)₃·9H₂O and PrCl₃. The reaction between them results in a mixture of compounds that transform into single-phase SrTiO₃:Pr³⁺,Al after annealing in air. Displacement of Ti out of the SrTiO₃ lattice caused by substitution with Al and formation of individual crystalline TiO₂ phase (rutile) were observed. PL spectra show the high-intense red peak (λ = 617 nm), the same high-intense peak with the full width at half maximum (FWHM) 20 nm was found in cathodoluminescence spectra. The increase of the aluminium concentration from 0 up to 15 mol.% leads to approximately two-fold increase in the luminance. The latter increases from 180 up to 350 cd/m² at the anode voltage 10 kV and current density 30 μA/cm² .