기초과학융합연구소

•연구자: 물리학과 이윤상, 위상원

•발표일: 2024.09

•DOI: https://doi.org/10.1016/j.optmat.2024.115900

•C.Y. Lee et al., Optical Materials (Q1), Volume 155, 115900 (2024)

•Abstract

We investigated the luminescent and optical thermometric properties of Er³⁺ and Yb³⁺ co-doped K₅Y(P₂O₇)₂ (KYP) with dependence on the excitation wavelength. To examine the role of Yb³⁺ ions in excitation-dependent luminescence, we synthesized three series of samples: an Er³⁺ singly doped KYP sample, and two Er³⁺ and Yb³⁺ co-doped KYP samples with varying concentrations of Er³⁺ or Yb³⁺. Although our samples exhibited visible and near-infrared (∼1550 nm) emissions under ultraviolet excitation, the doping with Yb³⁺ disturbed the luminescence of Er³⁺. In the case of 980 nm excitation, we identified upconversion luminescence (UCL) and 1550 nm luminescence; they were enhanced significantly via doping with Yb³⁺, which served as a sensitizer via energy transfer to Er³⁺. Our samples demonstrated excellent optical thermometric properties under 980 nm excitation compared with under ultraviolet excitation. In particular, the relative sensitivity of the UCL spectra was 1.01 %/K at 293 K. These results suggest the promising potential of using our Er³⁺ and Yb³⁺ co-doped KYP as an optical thermometer under 980 nm excitation.