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

Abstract

A dual purpose solid state electrochromic diode has been fabricated using polythiophene (P3HT) and ethyl Viologen (EV), predoped with multiwalled carbon nanotubes (MWCNTs) and MoS2. The device has been designed by considering two important aspects, first, the complementary redox activity of P3HT and EV and second, the electron holding properties of MoS2 and MWCNTs. The latter is found to enhance the electrochromic performance of the solid state device. On the other hand, the complementary redox nature gives the asymmetric diodic I–V characteristic to the device which has been exploited to use the electrochromic device for rectification application. The MoS2 nanoflower and MWCNTs are synthesized by one-step hydrothermal and pyrolysis techniques and well characterized by scanning electron microscopy (SEM), X-ray analysis (XRD), and Raman spectroscopy. Electrochromic properties of the device have been studied in detail to reveal an improvement in device performance in terms of faster speed and high coloration efficiency and color contrast. In situ bias-dependent Raman spectroscopy has been performed to understand the operation mechanism of the electrochromic diode which reveals (bi-)­polaron formation as a result of dynamic doping eventually leading to color change. A half-wave rectifier has been realized from the electrochromic diode which rectifies an AC voltage of frequency 1 Hz or less making it suitable for low frequency operation. The study opens a new possibility to design and fabricate multipurpose frequency selective electrochromic rectifiers.

Fano-Type Wavelength-Dependent Asymmetric Raman Line Shapes from MoS2 Nanoflakes

“…o exc (4) where λ o is the critical point energy corresponding to the electronic excitation at k = 0 in the band structure of MoS 2 and λ exc is the energy of laser excitation. The value of λ 0 has been estimated by analyzing the wavelength-dependent trend (by extrapolating the trend) which comes out to be ∼2.91 eV.…”

“…Light–matter interaction in transition metal chalcogenides like MoS 2 , MoSe 2 ,WS 2 , and WSe 2 has been widely explored to make next-generation photonics and optical devices by exploring their unique electronic, − optical, and spin-valleytronic and electrical properties. Among these, MoS 2 has gained tremendous attention due to its application in light detection, light emission, solar energy storage, field-effect transistors (FETs), , and so forth.…”

Bifunctional solid state electrochromic device using WO3/WS2 nanoflakes for charge storage and dual-band color modulation

“…It is well-known that the electrode material plays a vital role to achieve high-performance ESCs, which contain a series of active electrodes including metal oxides/dichalcogenides, carbon-based materials, MOFs, conducting polymers, and their composites. [13][14][15][16][17][18][19][20][21][22][23] Some transition metal oxides or conducting polymers such as polythiophene, polyaniline, WO 3 , V 2 O 5 , MnO 2 , etc. are widely used active materials for both electrochromic and energy storage applications due to their faradic reactions between the active material and electrolyte.…”

Exploiting Charge Storage Capabilities of NiTiO3/TiO2 for Achieving the Most Efficient Hybrid Electrochromic Device

“…Various electrochromic materials span over the families of organic materials, inorganic materials, metal complexes, , metal–organic frameworks (MOFs), organometallics, and polymers . Among them, organic materials and their derivatives such as polythiophene, , polyaniline, viologen, polypyrrole, perylene bismides, carbazole, naphthalene diimide, and Prussian blue have the advantages of easy synthesis, high color contrast, and low cost, whereas inorganic materials such as transition metal oxides and perovskites such as WO 3 , ,, TiO 2 , V 2 O 5 , NiO, and NdNiO 3 prove to be robust when used as an electrode. Though several active materials are available, most of the time the performance of an ECD is limited due to poor design or lack of supporting material, which can facilitate the overall bias induced color switching process.…”