Electron Donor Ferrocenyl Phenothiazine: Counter Ion for Improving All-Organic Electrochromism

Abstract

Electron-donating properties of 3-ferrocenylethynyl-10-propyl-10H-phenothiazine (FPP) has been studied to be used as an efficient counter ion for application in a viologen-based organic electrochromic device to facilitate an efficient all-organic electrochromic device. The FPP molecule, when used as a counter ion with viologen, improves the switching time to less than half a second and exhibits lower operation voltage of ∼1 V and excellent stability for longer than 1800 s with a negligible amount of absorption loss. Spectroscopic and electrochemical measurement techniques have been used to understand the mechanism of bias-induced enhanced performance of the FPP−viologen-based solidstate electrochromic device. The device does not contain any liquid electrolytic medium to support its switching behavior and can also be fabricated on a plastic substrate for realization of a flexible all-organic electrochromic device. The viologen−FPP electrochromic device showed an optical contrast of more than 55% with a bias of 0 to 1 V when switched between OFF-(transparent) and ON-(blue) states. An excellent value of coloration efficiency of 460 cm 2 /C is obtained with a simple all-solid device geometry arrangement, making it the most efficient solid-state electrochromic device in the viologen family of devices.

Flexible organic optoelectronic devices on paper

“…undergo stable and reversible color changes under the action of an external electric field, and appear as reversible changes in color and transparency. Materials with electrochromic properties are called electrochromic materials, and devices made of organic electrochromic materials are called organic electrochromic devices (OECDs) ( Chaudhary et al., 2020 ; Che et al., 2019 ; Dov et al., 2017 ; Kim et al., 2019 ; Sonmez et al., 2004 ).…”

Bifunctional Application of Viologen-MoS2-CNT/Polythiophene Device as Electrochromic Diode and Half-Wave Rectifier

“…Electrochromism , is a phenomenon, shown by some material (known as electrochromic materials), of an electrical bias induced change in optical properties as can be seen through the naked eye and/or in terms of modulation in absorption or transmission spectrum. An electrochromic device (ECD), fabricated utilizing the electrochromic properties of any material, is mainly used for applications in electronic curtains, smart windows, color filters including heat shielding, and so forth. − However, recently such devices have gotten a lot of interest due to additional applications in various fields like storage devices, − sensors, − special displays, − and other electronic circuits . A typical ECD comprises thin films of electrochromic materials, ion transport material (electrolyte), and sometimes counterions that help to enhance the performance of the device.…”

Improved ionic solid/viologen hybrid electrochromic device using pre‐bleached Prussian‐blue electrode

“…Electrochromic devices [7,8], helps in achieving this and makes research in the field more fascinating. Devices that reversibly switch their optical properties on application of an external bias are categorised as electrochromic devices [9][10][11][12]. They do so because of their capabilities to exist in variable oxidation states and have different optical properties correspondingly.…”