An intrinsically stretchable and bendable electrochromic device

Abstract

Stretchable electrochromic devices were fabricated from electrospun PEDOT:PSS (poly(3,4-ethylenedioxythiophene):polystyrene sulfonate) fibers. Stretchable and transparent electrodes with a sheet resistance of 1200 Ω/sq were prepared by depositing the conductive fibers on elastomeric substrates that were prepared from polydimethylsiloxane. The conductive substrates replaced the ITO coated glass electrodes that are typically used in electrochromic devices. The functioning device was prepared from a flexible chitosan electrolytic gel and a 4,7-bis(4-diphenylaminophenyl)-2,1,3-benzothiaziazole (TPA-BZT-TPA) electrochrome that were deposited on the streatchable transparent electrodes. The assembled device could be stretched to 150% its original length and bent to a curvature of 0.1. The device could be operated and switched between its yellow (off) and blue (on) states while being stretched and bent with a maximum contrast ΔT ≈30% at 805 nm and a coloration efficiency of 168 cm2/C. The stretchable device had an electrochromic contrast that was 30% greater than its counterpart that was prepared from conventional ITO-glass electrodes. The critical composition required for making devices truly stretchable was possible by evaluating the performance of five types of devices consisting of different layers.

Recent advances in nanofiber-based flexible transparent electrodes

“…Electrochromic refers to the stable and reversible change of color and transparency of materials under the influence of external electric field [10]. Electrochromic devices have garnered significant interest because of their potential uses in smart windows, reflective displays, electronic shelf labels, electronic billboards and so on [321][322][323][324]. Electrochromic materials are divided into inorganic and organic electrochromic materials.…”

Intrinsically Stretchable Integrated Passive Matrix Electrochromic Display Using PEDOT:PSS Ionic Liquid Composite

“…An additional device was reported recently that used electrospun PEDOT:PSS fibers to form stretchable electrodes, onto which electrochromic material was deposited, which could be stretched to 150% strain, with a transmission change of 30% at the wavelength of maximum change. 36 The present work progresses to a fully integrated stretchable electrochromic device comprising intrinsically stretchable layers, integrated electrode contacts, and encapsulation, that shows high contrast, rapid switching, and cyclability under 30% strain. The step taken to a 3 × 3 passive matrix display demonstrates the feasibility of scaling up to larger displays.…”

“…It employs a stretchable electrolyte as well, but it is water-based, and so can be susceptible to dehydration. An additional device was reported recently that used electrospun PEDOT:PSS fibers to form stretchable electrodes, onto which electrochromic material was deposited, which could be stretched to 150% strain, with a transmission change of 30% at the wavelength of maximum change …”

Enhancing the performance of transparent and highly stretchable organic electrochemical transistors by acid treatment and copolymer blending of electrospun PEDOT:PSS fibers

“…We leveraged this knowledge to fabricate stretchable OECTs and an all-organic electrochromic device from electrospun PEDOT:tosylate and PEDOT:PSS fibers. 52 Although the devices were both stretchable and bendable, their performance was limited compared to their conventional counterparts. Indeed, the performance of the devices deteriorated with successive stretch/release cycles.…”