The team of the University of Science and Technology of China has developed an intelligent color-changing "glass", which is expected to be used in energy-saving buildings and other fields

On December 14, the surging news learned from the University of Science and Technology of China that the team of academician Yu Shuhong of the university recently developed a new type of low-cost intelligent color-changing "glass" - multi-color display electrochromic device. The device can not only achieve multi-color display, but also can achieve self-powered drive, and is expected to be used in energy-saving buildings, low-power displays, anti-glare rearview mirrors and other fields in the future. The relevant results were recently published in nano express.

According to the R&D team, tungsten oxide is considered to be one of the most promising electrochromic candidates because of its high optical transmission modulation rate and excellent cycle stability. However, its single color change is not conducive to application in areas such as multicolor displays. The use of techniques such as element doping, material synthesis, and special structural design can solve the defects of the monotonous color of tungsten oxide, but there are still shortcomings of high cost or sacrificing transparency.

Academician Yu Shuhong's team developed a multi-color display electrochromic device based on nanowire assembly, which integrates tungsten oxide and vanadium oxide nanowires together by using interface assembly technology, so that the device has specific optical, electrical and multicolor display characteristics. Under the application of different voltages, the assembly can exhibit dynamic color changes from orange, green to gray. By controlling the proportion of the two nanowires, the color display, transparency, response time, coloring rate and other electrochromic properties of the assembled film can also be controlled. In addition, with the assistance of mask plates, interface assembly technology can achieve more complex color display and information transmission by constructing various patterns and regulating components.

Most of the traditional electrochromic devices are based on the preparation of indium tin oxide conductive glass, which requires the help of an external power supply system to drive, which affects the flexibility, independence and portability of the device. In order to solve this problem, Wang Jinlong, a special associate researcher of the team, was inspired by the concept of primary batteries, and integrated the primary battery system into the silver nanowire transparent conductive electrode based on high stability and flexibility and the tungsten oxide nanowire electrochromic film, and successfully developed a self-powered, low-cost flexible electrochromic device. Compared to external power supplies, this self-powered electrochromic transformer avoids internal resistance and improves the average coloring efficiency by about 20 percent; after 450 electrochromic cycle cycles, only about 6.8 mg of aluminum sheets per square centimeter device is consumed.

In addition, as a smart window, the device also exhibits good sunlight radiation regulation performance, compared to the faded state, the window coloring can reduce the average temperature of simulated sunlight irradiation objects from 33 degrees Celsius to 25.6 degrees Celsius.