The enhanced up-conversion green by Yb-Mn dimer in NaBiF₄:Yb³⁺/Er³⁺/Mn²⁺ for optical fiber temperature sensor

Through doping Mn²⁺ into the NaBiF₄:Yb³⁺/Er³⁺, it can be achieved that NaBiF₄ :Yb³⁺/Er³⁺/Mn²⁺ possess superior temperature sensing performance and application in temperature optical fiber sensing on the premise of enhancing the green emission upon the 980 nm excitation. The effect of Mn²⁺ content on the phase and luminescence of NaBiF₄:Yb³⁺/Er³⁺/Mn²⁺ is investigated by X-ray diffraction (XRD) and fluorescence spectrophotometer characterization. The up-conversion (UC) green emission intensity is enhanced by 3 times by Mn²⁺ doping. The Yb³⁺-Mn²⁺ dimer is introduced to clarify the mechanism of UC red and green emission enhancement, where involved in is three-photon process. Moreover, the optical thermometric behaviors of the synthetic compounds are analyzed according to the fact that Er³⁺ processes a couple of green emission levels ²H_11/2 and ⁴S_3/2, and the maximum S_a (absolute sensor sensitivity) reaches 0.00559 K⁻¹. The preliminary design and application of NaBiF₄:Yb³⁺/Er³⁺/Mn²⁺ as a probe in the temperature optical fiber sensor has been carried out, suggesting that NaBiF₄: Yb³⁺/Er³⁺/Mn²⁺ is expected to be a kind of promising material for non-contact optical thermometer.