Fig. 1. XRD patterns of YOF-HY submicron crystals

Fig. 2. SEM micrographs of YOF-H₁Y₂ submicron crystals

Fig. 3. Elemental mappings and EDS spectrum of YOF-H₁Y₂ submicron crystals

Fig. 4. Upconversion spectra of different doping ratios of YOF-H_uY_{vsubmicron crystals under 977 nm excitation}

Fig. 5. Up-conversion spectra of YOF-H₁Y₂ crystals under different power densities and dependence of emission intensities on excitation powers

Fig. 6. Energy level transfer mechanisms of Ho³⁺ and Yb³⁺ in YOF submicron crystals under 977 nm laser excitation.

Fig. 7. Spectral power distributions and net photon distributions of YOF-H₁Y₂ submicron crystals at different pump power densities at 977 nm laser excitation

Fig. 8. Upconversion spectra， fluorescence integral intensity ratio， absolute and relative sensitivity curves of YOF-H₁Y₂ submicron crystals at different temperatures

Fig. 9. Upconversion temperature cyclic fluorescence integral intensity ratio cycle trend curve of YOF-H₁Y₂ submicron crystals