Enhanced near-infrared emission of Er3+ as a synergistic effect of energy transfers in Bi3TeBO9:Yb3+/Er3+ phosphors

• Published in: Journal of luminescence 2023-06, Vol.258, p.119774, Article 119774
• Main Authors: Zhezhera, T., Gluchowski, P., Nowicki, M., Chrunik, M., Majchrowski, A., Kasprowicz, D.
• Format: Article
• Language: English
• Subjects: Bi3TeBO9; Luminescence; Rare earth ions; Solar cells; Spectral converters
• ISSN: 0022-2313; 1872-7883
• DOI: 10.1016/j.jlumin.2023.119774

Enhanced near-infrared emission at 1531 nm of Er3+ ions excited by Bi3+ and/or Yb3+ ions was revealed in Bi3TeBO9:Yb3+/Er3+ phosphors. The microcrystalline powders investigated: Bi3TeBO9:Er3+, Bi3TeBO9:Yb3+ and Bi3TeBO9:Yb3+/Er3+ were synthesized by means of the modified Pechini method. Their hexagonal structure with P63 space group was confirmed by XRD measurements. The morphology of the above-mentioned samples was analyzed using SEM technique. The results of μ-Raman investigations showed low phonon energy of Bi3TeBO9 matrix. The characteristic Er3+ emission at 1531 nm assigned to the 4I13/2 → 4I15/2 transition in Bi3TeBO9:Er3+ and Bi3TeBO9:Yb3+/Er3+ powders was excited by Bi3+ or Yb3+ ions (the 1S0 → 3P1 or 2F7/2 → 2F5/2 transitions) upon their excitation at 327 or 975 nm, respectively. It was revealed that the effective energy transfer from the excited Bi3+ ions (at 327 nm) directly to Er3+ ions or indirectly to Er3+ ions both via the excitation of Bi3+ ions in VIS range or excitation of Yb3+ ions in the NIR range results in synergistic effect, which produces enhanced emission at 1531 nm of Er3+ ions in Bi3TeBO9:Yb3+/Er3+ system. Moreover, it was found that the effective energy transfer from the excited Yb3+ ions (at 975 nm) directly to Er3+ ions results in the efficient emission at 1531 nm of Er3+ ions. Furthermore, the calculations of energy transfer efficiency and quantum efficiency proved the effective energy transfer from Bi3+ to Yb3+ and from Yb3+ to Er3+ ions. The corresponding mechanisms of energy transfer processes in the investigated materials were discussed on the basis of reflectance, excitation and emission spectra and measured decay times. The results indicate a potential of the use of Bi3TeBO9:Yb3+/Er3+ powders as spectral converters in new generation of photovoltaic devices. [Display omitted] •Bi3TeBO9 microcrystalline powders doped with Yb3+ and Er3+ ions were synthesized by means of the modified Pechini method.•Enhanced near-infrared emission of Er3+ as a synergistic effect of energy transfers in Bi3TeBO9:Yb3+/Er3+ phosphors.•Bi3TeBO9:Yb3+/Er3+ powders can be potentially used as spectral converters in new generation photovoltaic devices.