All-Printed Multilayers and Blends of Poly(dioxythiophene) Derivatives Patterned into Flexible Electrochromic Displays

Low-cost, flexible and thin display technology is becoming an interesting field of research as it can accompany the wide range of sensors being developed. Here, the synthesis of poly(dimethylpropylene-dioxythiophene) (PProDOT-Me₂) by combining vapor phase polymerization and screen printing is presented. A multilayer architecture using poly(3,4-ethylenedioxythiophene) (PEDOT) and PProDOT-Me₂ to allow for electrochromic switching of PProDOT-Me₂, thereby eliminating the need for a supporting transparent conductive (metal oxide) layer is introduced. Furthermore, the technology is adapted to a blended architecture, which removes the additional processing steps and results in improved color contrast (?E* > 25). This blend architecture is extended to other conductive polymers, such as PEDOT and polypyrrole (PPy), to highlight the ability of the technique to adjust the color of all-printed electrochromic displays. As a result, a green color is obtained when combining the blue and yellow states of PEDOT and PPy, respectively. This technology has the potential to pave the way for all-printed multicolored electrochromic displays for further utilization in printed electronic systems in various Internet of Things applications.