Temperature sensitivity based on Er3+ fluorescence fluctuation in Gd2Ti2O7: Er3+-Yb3+ porous nanofibers.

(Gd 1−x−y Er x Yb y) 2 Ti 2 O 7 (GTOEY) fibers were synthesized by electrospinning technique and heat-treatment processes, in which nano-scale fibers vested with homogeneous porous morphology, high crystallinity and elevated temperature heat-resistance. Under 977 nm laser excitation, GTOEY nanofibers exhibit effective frequency upconversion (UC) fluorescence, therefore, the violent green and dimmed red UC emissions are identified as two-photon absorption processes, attributing to 2H 11/2 /4S 3/2 → 4I 15/2 and 4F 9/2 → 4I 15/2 radiation transitions of Er3+, respectively. Moreover, the temperature sensitivity based on UC emission fluctuation of Er3+ over a wide temperature range of 303–633 K has been derived. Thereby, having used a 980 nm laser and achieved green UC luminescence of GTOEY fibers centered at 525 and 545 nm, the maximum absolute and relative sensitivity values are obtained to be 0.382% K−1 and 1.12% K−1, respectively. These significant results demonstrate that the GTOEY nanofibers with distinct porous structure and admirable photothermal sensitivities can be regarded as a promising temperature sensing material used for overheating alarm and safety protection equipment. Relationship between sensitivity (S A and S R) and temperature of porous Er3+/Yb3+ doped Gd 2 Ti 2 O 7 (GTOEY) nanofibers in the range of 303–633 K. Image 1 • Porous Gd 2 Ti 2 O 7 : Er3+/Yb3+ (GTOEY) nanofibers were prepared by electrospinning. • Upconversion emissions of Er3+ are identified as two-photon absorption processes. • GTOEY nanofibers exhibit high temperature sensitivity based on FIR technique. • Maximum S A and S R values are derived to be 0.382% K−1 and 1.12% K−1, respectively. • GTOEY provide a new perspective in temperature sensing for overheating alarm. [ABSTRACT FROM AUTHOR]