Structure and up-conversion luminescence of Yb3+/Ho3+ co-doped fluoroborate glasses

Yb3+/Ho3+ dual-doped fluoroborate glasses were obtained by high temperature melting process. Ultraviolet-visible spectrophotometer, XRD, FT-IR and fluorescence spectrometer were used to characterize the glass structure, transmittance, up-conversion (UC) emission spectrum and fluorescence decay time. The structural groups in all glasses were [BO4], [BO3] and [PO4] units. Transmissivity of all glass samples exceeds 60%. In addition, the fluorescence intensity ratio (FIR) technique was used to investigate the variation of UC luminescence at 543 nm (Ho3+: F-5(2)-> I-5(8)) and 659 nm (Ho3+: F-5(2)-> I-5(8)) under pump wavelength of 980 nm between 453 K and 653 K. The absolute sensitivity of glass sample at 653 K was 5 x 10(-2) K-1 and the relative sensitivity was 9 x 10(-4) K-1. The results indicated that Yb3+/Ho3+ co-doped fluoroborate glass has potential applications for up-conversion luminescence and optical temperature measurement.