Fig. 1. Luminescence mechanism of mechanoluminescent materials^{[7, 40]}. (a) Trap control type; (b) non-trap control type

Fig. 2. Core structure of mechanoluminescent fiber^[9]. (a) Preparation and structure diagram of mechanoluminescent composite fiber; (b) (c) side SEM images of the mechanoluminescent fiber without outer PDMS at low and high magnification; (d) (e) cross section SEM images of the mechanoluminescent fiber at low and high magnification; (f) the change of mechanoluminescence intensity of mechanoluminescent fiber during repeated stretching and relaxation

Fig. 3. Mechanoluminescent fiber based on cross-shaped elastic fiber^[10]. (a) Preparation and structure diagram of mechanoluminescent fiber combined with ZnS∶Cu/PDMS and cross-shaped fiber; (b) SEM images of the cross-shaped fiber (top left) and the mechanoluminescent fiber (top right) and mechanoluminescence images during fiber stretching (bottom); (c) mechanoluminescence spectra of fiber stretched at different strain rates; (d) the change of mechanoluminescence intensity of fiber during cyclic stretching and release

Fig. 4. Schematic diagrams of mechanoluminescent fiber structure^[46]. (a) Structure diagram of distributed organic mechanoluminescence fiber; (b) a dental retainer structure diagram of integrated mechanoluminescent fiber

Fig. 5. Ba₂LaF₇∶Tb³⁺ glass-ceramics mechanoluminescence fiber^[40]. (a) Photo of glass-ceramics sample and its mechanoluminescence photo with knife scratching; (b) mechanoluminescence spectra and digital photos of glass-ceramics with different scraping forces; (c) photograph of the Ba₂LaF₇∶‍Tb³⁺ glass-ceramics fiber under ultraviolet light; (d) mechanoluminescence photos (left) and light intensity distribution (right) of glass-ceramics fiber after friction in different parts; (e) diagram of stress distribution detection using Ba₂LaF₇∶Tb³⁺ glass-ceramics fiber; (f) curve of light intensity ratio at both ends of fiber with friction position (left) and application diagram of railway traffic monitoring (right)

Fig. 6. Potential applications of mechanoluminescent fiber^{[40, 47-48]}. (a) Underwater rescue; (b) road and bridge health and traffic monitoring; (c) tailor-made wearable mechanoluminescent textiles for human health and exercise monitoring; (d)-(f) smart textiles woven with SOEFS and spandex alternating as warp yarn and cotton as weft yarn for fabric display and motion sensing