Multipurpose Flexible Sensor With Photochromic And Electrochromic Properties

In recent years,with the continuous development of flexible electronic technology,The demand for all kinds of intelligent wearable devices is gradually increasing.As the preferred material for flexible devices,hydrogel has an excellent flexible and extensible ability.Electronic devices based on hydrogel electrolytes have also been widely used.Based on the fact that transition metal oxides have photochromic and electrochromic properties,this paper prepared a kind of organic-inorganic composite material with color-changing properties by mixing Mo O_3-x hybrid and conductive polymer PEDOT:PSS.A flexible strain sensor with photochromic and electrochromic properties is assembled that Mo O_3-x/PEDOT:PSS was coated on ITO/PET,and then combined with organic hydrogel electrolyte.Next,the structure and performance of the sensor are tested.The micromorphology of the device is analyzed by SEM and TEM.The discoloration performance of the device was characterized by UV-vis spectrophotometer.The results show that the device can achieve instantaneous discoloration under low voltage and UV light,and the discoloration time is less than 2 s.The fade of the device can complete within 10 s by applying voltage in a reverse direction.The rapid coloring and fading process can maintain about fifty cycles.When part of the solvent in the gel electrolyte is replaced by organic solvent,the device can still have electrochromic and photochromic properties at-20℃.But the response time is relatively slow about 2 s for UV light and 8s for electricity,respectively.Finally,the performance that the sensor respond to external strain is explored.When the external force is applied,the device can respond quickly and clearly,and the strain coefficient is 0.9.In this paper,the combination of transition metal oxide and conductive polymer makes the material not only has photochromic and electrochromic properties,but also improves the speed of color change response.Moreover,the maintenance of its performance at low temperatures also provides a new idea for the design of flexible strain sensors in the future.