ZFP+PU/PVDF composite fibers based on ZnS:Cu phosphors for low temperature lighting monitoring sensor devices

Highlights: • A novel long-afterglow luminescence composite fiber was fabricated. • The fiber with long-afterglow luminescence happened in ultra-low temperature. • The fiber has good flexibility, elasticity and mechanical properties. • Various light-emitting devices were woven by the fiber. ZnS is one of the typical representative materials of II-VI direct bandgap semiconductors, and its photoluminescence (PL), mechanoluminescence (ML), and electroluminescence (EL) have already been extensively studied. Herein, ZFP + PU/PVDF composite fibers based on ZnS:Cu phosphors were fabricated for low-temperature lighting monitoring sensor devices, whose long-afterglow luminescent light-emitting process went from slowly brighter to slowly dim as the temperature changed. Impressively, the shell-core structure of ZnS doped with PVDF-HFP particles (ZFP particles) can enhance the light intensity duration by up to 100 s. Different from the pure ZnS:Cu phosphors, the luminescence mechanism of ZFP particles was the synergy of the piezoelectric effect in addition to the stimulating effect of temperature. Otherwise, using PU/PVDF as a substrate can endow the fiber with good flexibility, elasticity, and mechanical properties. Then, to confirm whether the shape changes affect the luminescence, the device of the ropes and fabrics woven by the fibers were further characterized. The results suggested that the tightness of the devices was an extrinsic factor influencing luminous intensity. In summary, this study presents a new luminescence concept with profound research prospects.