Sr₂GdF₇: Er³⁺/Yb³⁺ nanocrystal-inlaid pliable fibers for synergistic feedback temperature monitoring

Sr₂(Gd_1-x-yEr_xYb_y)F₇/polyacrylonitrile(SGF-EY/PAN) is fabricated with nanocrystal-inlaid fiber (NIF) structure via electrospinning, which possesses synergistic feedback and real-time temperature monitoring. Under near-infrared laser radiation, SGF-EY fibers have the advantage of more efficient upconversion luminescence, which is a viable option to achieve dual thermal feedback at specific power condition. The relative sensitivity (S_R) of the principal thermal feedback (I₅₂₃/I₅₄₀), a significant portion to evaluate the reliability of temperature monitoring, reaches a maximal value of 0.856%K⁻¹ at 303 K. Additionally, the peak ratio of the 523 nm green radiation influenced by two-photon absorption and the 410 nm blue radiation controlled by three-photon absorption is employed as an auxiliary indicator (I₅₂₃/I₄₁₀) that attains a maximum S_R of 1.456%K⁻¹ at 303 K, providing a thermal sensing with synergistic response effect. The nanocrystal-inlaid pliable fibers with dual temperature feedback suggest potential application prospects in the fields of noncontact biomedical temperature sensor, aeronautical engineering probe and flexible thermal monitoring component.