Solar Energy Storage Silks via Coaxial Wet Spinning

Abstract

Near-infrared\n(NIR) radiation has widely been applied for phototherapy\ndue to its beneficial thermal effect on human tissue. However, desirable\nthermal textiles have not been actualized by implementing this radiation\ninto textile fiber. Herein, persistent NIR-emitting fibers have been\nfabricated by incorporating long-lasting phosphorescent phosphor and\nfluorescent Ag₂S quantum dots (QDs) into the regenerated\nsilk fibroin (SF)-based core–sheath fibers. Green-emitting\nphosphor was introduced into the fiber core during coaxial wet spinning,\nwhile various layers of QDs emissive in NIR range were deposited on\nthe fiber surface. A double-layered hollow structure was obtained\nin these fibers with improved surface uniformity. Fluorescence spectrometry\nconfirmed that the green emission of the embedded phosphors (i.e.\n492 nm) was absorbed by the surface Ag₂S layer to give\ncontinuous NIR emission. Up to 13.5 % of the 993 nm NIR radiation\npassed through porcine epidermis of 0.25 mm thickness. This work has\nshed new light on the fabrication of self-warming fiber, which is\nanticipated to be applied in various fields such as continuous warming\ntextiles and wearable phototherapy devices.