Facile synthesis and multicolor up-conversion luminescence of BaF2:Yb3+, Ho3+ nano-fibers

Abstract

In order to enrich the morphology of alkaline earth metal fluoride family, BaF₂:Yb³⁺, Ho³⁺ nano-fibers are innovatively designed and constructed by applying single-axis electrospinning combined with twi-crucible fluorination technology without applying protective gas. All specimens display obvious fiber-like morphology and exhibit excellent up-conversion luminescence (UCL) performance. The higher emission peak of BaF₂:Yb³⁺, Ho³⁺ nano-fibers at 544 nm is attributed to ⁵S₂/²F₄→⁵I₈ and the lower peak at 656 nm comes from ⁵F₅→⁵I₈ when excited with 980 nm laser excitation. It is found that the luminescent colors of all the specimens fall within the green-light zone via controlling the concentration of Ho³⁺ ions. The correlated color temperature range of the BaF₂:Yb³⁺, Ho³⁺ nano-fibers is 6514–6574 K. More notably, all specimens exhibit high color purity (the highest color purity can reach 99.8 %). In summary, we designed and prepared BaF₂:Yb³⁺, Ho³⁺ nano-fibers by applying single-axis electrospinning combined with twi-crucible fluorination technology. The luminescence mechanism and formational mechanism of BaF₂:Yb³⁺, Ho³⁺ nano-fibers are systematically studied, and the fabrication technique is founded. These new findings are helpful for the design and preparation of novel alkaline earth metal fluoride-based one-dimensional luminescent nanomaterials. The prepared BaF₂:Yb³⁺, Ho³⁺ nano-fibers have promising applications in fields such as dynamic colorful display, biological imaging, sensing, optical probes and catalysis.