Flexible Electrochromic V₂O₅Thin Films with Ultrahigh Coloration Efficiency on Graphene Electrodes

Abstract

Flexible multi-color electrochromic V 2 O 5 thin films have been prepared by electrochemical deposition on the double-layer Graphene/PET substrates. The deposited films have a layered structure with nano-crystals in the amorphous matrix, which contributes to an ultrahigh coloration efficiency of ∼555.83 cm 2 C −1 @800 nm and a large transmittance modulation of 68.94% @800 nm. The large interlayer distance of 1.20 nm, good electrolyte penetration, and short lithium ion diffusion distance make some key electrochromic parameters competitive in our proposed devices. The low-temperature-processed V 2 O 5 thin films on Graphene would provide us an opportunity to design and prepare flexible electrochromic devices.

Post-Synthetic Color Tuning of the Ultra-Effective and Highly Stable Surface-Confined Electrochromic Monolayer: Shades of Green for Camouflage Materials

“…While the obtained values are comparable to values previously reported by us for structurally related monolayer-based ECDs, , the values are significantly larger than that reported for the majority of metalorganic-based ECDs, where a value of 750 cm 2 /C is considered exceptional . The η values of our monolayer-based ECDs are drastically larger than that reported for viologen-based ECMs (<301 cm 2 C –1 ) ,, and inorganic metal oxide systems, where the coloration efficiency of ∼556 cm 2 C –1 was referred to as “ultrahigh” in its class. , There was one literature report on the organic-based ECD that demonstrated similarly high values of coloration efficiency (≥1240 cm 2 C –1 ) . In addition, the van der Boom group reported on ECDs based on polypyridine layer-by-layer architectures on the flat ITO glass electrodes that demonstrated a similar ultrahigh CE of 1488 cm 2 /C …”

“…52 The η values of our monolayer-based ECDs are drastically larger than that reported for viologen-based ECMs (<301 cm 2 C −1 ) 9,53,54 and inorganic metal oxide systems, where the coloration efficiency of ∼556 cm 2 C −1 was referred to as "ultrahigh" in its class. 55,56 There was one literature report on the organic-based ECD that demonstrated similarly high values of coloration efficiency (≥1240 cm 2 C −1 ). 49 In addition, the van der Boom group reported on ECDs based on polypyridine layer-by-layer architectures on the flat ITO glass electrodes that demonstrated a similar ultrahigh CE of 1488 cm 2 /C.…”

In Situ Raman Observation of Dynamically Structural Transformation Induced by Electrochemical Lithium Intercalation and Deintercalation from Multi‐Electrochromic V2O5 Thin Films

“…Details of the experimental procedure have been reported elsewhere. [ 10 ] After electrodeposition, the absolute ethyl alcohol was used to rinse the loosely bounded particles on the surface of the V 2 O 5 thin films. Finally, the samples were dried at 60 °C for 12 h in air.…”

“…[ 17 ] In terms of nanocrystal‐in‐glass V 2 O 5 thin films, we have proposed ex situ Raman spectroscopic analysis to identify a distinct difference of three vibrational modes of OVOVO, VO 3 bending, and VO stretching between colored and bleached states in our previous work. [ 10 ] Although such ex situ Raman spectroscopic characterization of the V 2 O 5 thin films has been widely considered, designing in situ strategy to uncover the dynamically structural transformation of nanocrystal‐in‐glass V 2 O 5 electrode in real‐time during its electrochemical lithium intercalation and deintercalation still needs to be experimentally explored further.…”

Electrochromism of Nanocrystal-in-Glass Tungsten Oxide Thin Films under Various Conduction Cations

“…Another example is that the porous structure of WO 3 film is helpful for promoting the electrolyte infiltration and alleviating the expansion of the WO 3 during H + (proton) insertion. 8 It is demonstrated that the EC performance (such as coloration efficiency and optical modulation) in well-ordered material structure exhibits inferior properties, as compared to the amorphous EC materials such as WO 3 , 7,9 V 2 O 5 , 10,11 and NbO x . 12 As stated previously, 12 electrochromic performance of indium tin oxide (ITO)-in-NbO x composites with nanocrystalin-glass is better than the undoped amorphous NbO x .…”