Low-temperature inkjet printing of amorphous polyacid solutions to fabricate flexible electrochromic

Electrochromism refers to the optical properties of materials (reflectivity, transmittance, absorption, etc.) The phenomenon of stable and reversible color change under the action of , which is manifested as a reversible change in color and transparency in appearance.In recent years, smart windows prepared from electrochromic materials are extremely promising in the field of building energy conservation, and their unique color-changing ability has attracted widespread attention.

 

Polyoxometalate is a new type of electrochromic material with high chemical stability and UV stability.There has also been extensive research on the relationship between polyacid structure, element composition and electrochromism.Its poor film-forming properties and easy fracture during bending limit its application in flexible thin-film devices and other fields.Based on this, the team of Professor Peng Junbiao from South China University of Technology prepared a bendable isometallic polyacid (IPT) flexible electrochromic film by using low-temperature inkjet printing technology.

 

This technology can prepare amorphous IPT films with smooth surface, low haze and not easy to break by inkjet printing technology at low temperature (<70 ℃).The research shows that, compared with the crystalline IPT film, the optical modulation capability of the amorphous film can be increased from 14.8% to 46.2%, and its cyclic voltammetry stability can be increased from 200 to 1800 cycles.In addition, since the amorphous thin film does not have a rigid crystal structure, its flexibility is also more excellent.After 1000 bending times (10 mm in diameter), the discoloration properties remained at a high level.  

 

Different from traditional metal oxides and flexible organic electrochromic systems, this work prepares amorphous IPT films for flexible electrochromic devices by a low-temperature solution method.This provides a new idea for the application of polyoxometalates in flexible electrochromic devices.