An Electrolyte‐Free Flexible Electrochromic Device Using Electrostatically Strong Graphene Quantum Dot–Viologen Nanocomposites

Abstract

A strong electrostatic MV(2+) -GQD nanocomposite provides an electrolyte-free flexible electrochromic device wih high durability. The positively charged MV(2+) and negatively charged GQD are strongly stabilized by non-covalent intermolecular forces (e.g., electrostatic interactions, π-π stacking interactions, and cation-π electron interactions), eliminating the need for an electrolyte. An electrolyte-free flexible electrochromic device fabricated from the GQD-supported MV(2+) exhibits stable performance under mechanical and thermal stresses.

A facile one step electrostatically driven electrocodeposition of polyviologen–reduced graphene oxide nanocomposite films for enhanced electrochromic performance

“…53.7 and À25.2 mV, respectively. The partial negative charge on rGO is compensated by the highly positively charged PV and neutralized into a value of 25.1 mV for PV-rGO composite, suggesting the intermolecular non-covalent interactions between PV and rGO sheets [31]. These results are well supported by the photoluminescence measurements (Fig.…”

“…On the other hand, rGO based NiO hybrid films has shown to possesses faster switching times and better cycling performance owing to the better electrochemical stability and porosity of rGO which facilitates the electrolyte access [30]. Very recently, E. Hwang et al developed a flexible EC system comprising methyl viologen and graphene quantum dots that showed excellent EC switching and operational stability [31]. Consequently, the low cost and fast electron transfer kinetics made rGO a prominent electrode material for future ECDs.…”

Effects of Pre-reducing Sb-Doped SnO2 Electrodes in Viologen-Anchored TiO2 Nanostructure-Based Electrochromic Devices

“…Therefore, Li + ion diffusion lengths for electrochromic switching are minimized and sub-second switching speeds can be realized. Since this breakthrough, ultrafast electrochromic devices based on VTO nanostructurebased electrodes have attracted significant attention [19]- [21]; viologen-graphene systems have also drawn much attention [22], [23]. We note here that a counter electrode is a very important component of an electrochromic device.…”

Flexible and Stretchable Optoelectronic Devices using Silver Nanowires and Graphene

“…Electronic coupling between the graphene and the molecules through a covalent bonding reduced the contact resistance. Molecular monolayers between the graphene sheets showed a molecular-length-dependent current [ 37 ] Copyright 2014, John Wiley and Sons. c,d) Photoswitching mechanism of azo-based molecular electronics (c) and on/off current density (d).…”

“…[ 37 ] Common electrochromic devices have used an electrolyte to support the electrochromic reaction between electrodes. Metal cations with organic solvent were widely used as an ion-conducting medium, but such an electrolyte can decompose the electrochromes at high voltage and exhibits low stability in fl exible electrochromic systems.…”