A white phosphor based on oxyfluoride nano-glass-ceramics codoped with Eu3+ and Tb3+: Energy transfer study

Strontium fluoride nanocrystals doped separately with Ln(3+) = Eu3+ or Tb3+ ions (95SrF(2)center dot 5LnF(2)), as well as co-doped with both the ions (95SrF(2)center dot Eu4Tb) were synthesized for comparison. Then, glass-ceramics consisting of the mono-doped or di-doped SrF2 nanocrystals incorporated into amorphous silica (90SiO(2)center dot 9.5SrF(2)center dot 0.5Ln or 90SiO(2)center dot 9.5SrF(2)center dot 0.1EuF(3)center dot 0.4Tb) were prepared by sol-gel procedure. The studied materials were characterized by XRD, while the glass-ceramics additionally by SEM and BSE (backscattered electrons) techniques. Luminescence emission and excitation spectra of the doubly doped materials exhibited presence of such effects as simultaneous independent excitation and energy transfer Tb3+ -> Eu3+ as well as cross-relaxation in the materials with Tb3+ dopant. Tb3+ lifetime in 90SiO(2)center dot 9.5SrF(2)center dot 0.5EuF(3)center dot 0.4TbF(3) was distinctly reduced compared to 90SiO(2)center dot 9.5SrF(2)center dot 0.5TbF(3) probably by the Tb3+ / Eu3+ energy transfer. Owing to blue emission of SiO2, green light emitted by Tb3+ and red one by Eu3+ the 90SiO(2)center dot 9.5SrF(2)center dot 0.5EuF(3)center dot 0.4TbF(3) nano-glass-ceramics can play a white phosphor role. (C) 2017 Elsevier B.V. All rights reserved.