Optimizing Nd/Er ratio for enhancement of broadband near-infrared emission and energy transfer in the Er3 +–Nd3 + co-doped transparent silicate glass-ceramics

•NIR emission of Er–Nd has significantly enhanced after heat treatment changing times.•Broadband NIR of Er–Nd with an FWHM extending from 1250 to 1700 nm could be 340 nm.•NIR emission of Er–Nd, which covered the whole O, E, S, C, L and U bands was observed.•NIR emission bands at 1065 and 1546 nm are best for Nd/Er ratio of 2.5.•Energy transfer processes between the Nd3 + and Er3 + ions were also discussed.

The optimizing Nd/Er ratio for enhancement of broadband near-infrared (NIR) emissions in the Er3 +–Nd3 + co-doped SiO2–AlF3–BaF2–TiO2–CaCO3 (SABTC) transparent silicate glass-ceramics containing BaF2 nanocrystals under 808 nm excitation was investigated. The broadband NIR emission bands from 850 to 1700 nm, which covered the whole O, E, S, C, L and U bands were observed in the Er3 +–Nd3 + co-doped glass-ceramics samples, as a result of the overlap of Nd3 +-doped emission band centered at 1342 nm and the emission from 4I13/2 → 4I15/2 transition of Er3 + band centered at 1546 nm. The NIR emission intensity of Er3 +–Nd3 + co-doped bands centered at 895, 1065, 1342 and 1546 nm, becomes stronger with varied depending on the mixing ratio of Nd3 + and Er3 + ions, and the full width at half-maximum (FWHM) extending from 1250 to 1700 nm could be 340 nm. Most NIR emission bands at 1065 and 1546 nm are observed for the SABTC-1.0N0.4E glass-ceramics sample, corresponding to Nd/Er ratio of 2.5. At the same time, the energy transfer processes between the Nd3 + and Er3 + ions were also discussed.