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Ebraheem Azhar1 Hongbin Yu1

1, Arizona State University, Tempe, Arizona, United States

Electrochromic materials and films can be used as a non-emissive technique for display applications. Such technique has already been used in cars’ antiglare rearview mirrors, smart windows intended for energy savings for buildings. However, most of the electrochromic materials are deposited on rigid substrates, which will prevent it from being used in flexible and stretchable electronics applications, where low temperature deposition technique is desired. In this work, we explore the electrochromic materials and their inkjet-printing process onto flexible and stretchable substrates. A set of four inks based on the combination of synthesized WO3 nanoparticles, com- mercial WO3 nanoparticles, commercially obtained W-TiO2 and TiO2 nanoparticles, PTA, and oxylic acid dihydride (OAD) were mixed in isopropanol. The relative weights of each mixture were based on a previously reported D-optimal ink formulation. The ink was diluted 1/10 after initial mixture, and patterns were printed 33 times using a Microfab Jetlab II printer. An Autolab Potentiostat/Galvanostat was used to perform Cyclic voltammetry mea- surements at the specified voltages. A four-channel Arbin system was used to perform Galvanostatic chargedischarge measurements. The micrstructure of the nanoparticles used in this study were examined under scanning electron microscopy for examining nanoparticle morphology , x-ray diffraction for chemical and structural characterization, and dynamic light scattering for particle size determination. Electrochromic layers are then ink-jet printed on flexible and stretchable PDMS substrates, using synthesized Ag nanowires as conductive, yet highly transparent electrodes. The stretchable printed electrochromic device under various stress conditions are studied and electrochromic performances are evaluated that demonstrates clear switching behavior under external bias voltage. Detailed performance will be discussed.

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