Fig. 1. Preparation of the QD-doped photoresist. (a) Chemical components for the base photoresist; (b) CdSe/ZnS QD with a core-shell structure; (c) schematic of QD-doped photoresist

Fig. 2. Spectrum of CdSe/ZnS QD-doped photoresist. (a) Absorption; (b) PL spectra

Fig. 3. Schematic of a TPP 3D printing system

Fig. 4. Microscopic characterization of the TP-printed microstructure at the fiber end. (a) Optical microscope image; (b) SEM image; (c) fluorescence microscope image

Fig. 5. Schematic of the experimental system for temperature sensing

Fig. 6. Temperature sensitivity measurements. (a) Fluorescence spectra of a cylinder detector with a diameter of 50 μm and a height of 25 μm, recorded at different temperatures; (b) temperature-wavelength linear fitting curve; (c) temperature sensitivity of cylinder detectors with the same diameter and different heights (scale bar: 10 μm)

Fig. 7. Temperature sensitivity measurements. (a) Fluorescence spectra of a cylindrical detector with a diameter of 70 μm and a height of 10 μm, recorded at different temperatures; (b) measured temperature as function of the PL peak wavelength; (c) temperature sensitivity of cylindrical detectors with the same height and different diameters (scale bar: 10 μm)

Fig. 8. Long-term PL stability of the QD-based fiber optical temperature sensor at 26 ℃ and 70 ℃ over 48 h