MoS2doping and concentration optimization for application-specific design of P3HT-viologen-based solid state electrochromic device

Abstract

Methods to improve the performance of solid state electrochromic devices (ECDs) need to be explored and the dynamic doping process must be optimized to achieve ideal device performance. Molybdenum disulphide (MoS2) doped ECD has been fabricated by using two conducting polymeric films, i.e. polythiophene (P3HT) and ethyl viologen (EV), to investigate the role of 2D material doping on the overall device performance. Hydrothermally grown MoS2 nanoflowers, characterized using X-ray diffraction, electron microscopy and Raman spectroscopy were used for this purpose. Furthermore, the effect of MoS2 dopant concentration on the performance of an EV/P3HT-based ECD was studied systematically. The prepared solid-state ECD shows improved electrochromic performance in terms of switching speed, color contrast and coloration efficiency while switching its color from one state to the other (magenta and blue) under a very small external bias (±1.4 V). The transition from colored to bleached state is fastest for the highest (0.3 wt%) MoS2-doped ECD, whereas the color contrast and coloration efficiency is maximum for the lowest (0.1 wt%) MoS2-doped device. The variation in electrochromic parameters as a function of dopant (MoS2) concentration reveals that an appropriate concentration must be chosen depending on the requirement © 2022 IOP Publishing Ltd.