2D-Layered Structure WS₂ Nanosheets with Improved Electrochromism for Organic-Based Device

Abstract

A solid-state electrochromic device is assembled via polythiophene (P3HT) and tungsten disulfide (WS2)-introduced ethyl viologen (EV) layers. The WS2 nanosheets are prepared via a facile one-step hydrothermal technique and investigated via scanning electron microscopy, X-ray diffractometer, and Raman spectra. The device exhibits enhanced electrochromic properties, such as response time (0.9 s/1.3 s), cyclic stability (1000 cycles), coloration efficiency (410 cm2 C-1), and reversible color switching from pink to blue, at the small applied potential (±1.6 V). This indicates that WS2 with graphene-like 2D-layered nanostructure has the weak van der Waals force between the layers, which can store and transfer electrical charges between the films and electrolytes, thus improving the carrier mobility, which is crucial for improving the properties of electrochromic devices. In addition, the introduction of WS2 promoted the device to become one of the most efficient polythiophene-viologen based devices. Therefore, this work provides a basis for the development of new electrochromic devices as alternatives to graphene-based devices.