Fabrication of Thermochromic Photonic Crystal Stickers with Highly Sensitive Response for Non-open Fire Sensing

Giving Timely warnings for fire is very crucial for fire prevention and the protection of people's lives and property. However, most current fire warning sensors give warnings above 200 °C, which are not conducive to efficient and accurate warnings. Therefore, it is important to develop high-temperature sensors that can give timely, portable warnings at low temperatures (100 to 200 °C). Herein, simple and portable nonopen flame thermochromic photonic crystal (PC) stickers were constructed using ZnS nanoparticles and polyethylene (PE) films as the main components. The structural color of the PC stickers changed due to the chain motion of PE chain, and the changement of the refractive index of the materials when heating. Thus, an early fire warning sensor (EFWS) was designed based on the structural color change of PC stickers. The EFWS can give timely and visible sensing in 0.8 s at 115 °C. The EFWS based on PC stickers can be combined with indoor surveillance cameras for nonopen fire warnings and key place monitoring (e.g., electrical equipment) in households, aircraft, electrical appliances, substations, etc.