Prussian Blue-Cobalt Oxide Double Layer for Efficient All-Inorganic Multicolor Electrochromic Device

Abstract

An "all-inorganic", fast, and power-efficient solid-state electrochromic device has been realized by choosing Co 3 O 4 and PB films as complementing electrodes. The prussian blue and cobalt oxide films have been synthesized via a simple galvanostatic method to achieve better film quality to be used in a device. Prior to fabricating a prototype solid-state device, the electrodes have been tested using in situ electrochemical and spectroscopic studies. This is followed by fabricating a solid-state device that shows switching between multiple colors with an applied bias of less than a couple of volts. A moderate color contrast of ∼40% with 1.5 s switching time has been observed with showing stability for more than 900 s of continuous switching. A redoxdriven electrochromic behavior of individual electrodes makes it possible for the solidstate device to show beautiful colors with a small applied bias. Electrochemical and spectroscopic measurements have been carried out to establish the possible mechanism of color switching shown by the device. Moreover, a coloration efficiency of ∼250 cm 2 /C makes it comparable to an "all-organic" or hybrid solid-state device, with its strong nature being an additional advantage.

Low voltage colour modulation in hydrothermally grown Ni‐Co nanoneedles for electrochromic application

“…The advent of nano dimension [11,12], underlines that different nanostructures of the same material also exhibit the property with greater improvement [12]. Therefore, a worldwide parallel study is conducted in either finding the new nano materials or designing new morphologies for achieving better performance of different applications [5,13,14]. A huge number applications of TMO like supercapacitor [15], field emission [16], sensors [17], photocatalytic [18], hydrogen/oxygen evolution [19], electrochromic [4] and so forth demonstrates excellent performance by incorporating the different dimension-based nanostructures like nanodot [20], nanosheet, nanorod [21], nanoneedle, nanoflakes [21] and so forth.…”

Polymeric Ion Conductors Based on Sono‐Polymerized Zwitterionic Polymers for Electrochromic Supercapacitors with Improved Shelf‐Life Stability

“…Another disadvantage of multilayer ECSs is the complex device fabrication involving multiple reactions and synthesis steps. [ 13–15 ]…”

“…Another disadvantage of multilayer ECSs is the complex device fabrication involving multiple reactions and synthesis steps. [13][14][15] DOI: 10.1002/marc.202100468 Similar to typical EC devices (ECDs), [16][17][18][19][20][21] a much simpler version of ECSs is a monolithic device, also referred to as an all-in-one device, which can be conveniently fabricated by inserting an EC electrolyte layer between two electrodes. [22,23] The device performance and functionality mainly rely on the properties of the electrolyte.…”

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

“…Actual mechanism behind electrochromic operation must be known to improve performance which varies depending on the material category such as organic [20], inorganic [21], coordination network complex [22], metallo-organic [23,24] etc. Prussian blue (PB) [25,26], an important coordination compound, has been explored for its electrochromic performance since 1978. It has a wide range of applications, beyond electrochromism, in sensors [27,28], electrocatalysis [29], hydrogen storage [30], energy storage system [31], fuel cells [32] etc.…”