Flexible and Reusable Non-woven Fabric Photodetector Based on Polypyrrole/Crystal Violate Lactone for NIR Light Detection and Writing

Rapid NIR light detection and/or writing has drawn much attention,but their practical applications have been limited by obtaining such NIR photodetectors.To address this problem,we have developed a simple and versatile strategy to prepare a non-woven fabric photodetector.The blue non-woven fabric photodetector has been prepared by coating photo-thermochromic ink(including crystal violet lactone(CVL)as the thermo-sensitive dye,polypyrrole(PPy)nanospheres as the photothermal component and hydroxyethyl cellulose(HEC)as the polymer matrix)on white non-woven fabric.When the blue fabric photodetector is irradiated by NIR(808-nm as model,0.75 W cm^(−2))laser,the discoloration occurs in 35 s,and higher laser intensity confers more rapid discoloration.This discoloration results from the photothermal effect of PPy which confers the elevation of temperature(>50℃)and then converts CVL to its leuco form(colorless).When the laser is turned off,the temperature drops to below the transition temperature(<43℃),and then CVL reverts to its initial blue color.Moreover,different figures and images can be easily printed on the fabric photodetector by 808 nm laser,and then they can be erased automatically under ambient conditions,with excellent cycling stability.Therefore,this fabric photodetector may act as a new platform for rapid NIR light detection and writing.