Flexible electrochromic devices based on tungsten oxide and Prussian blue nanoparticles for automobile applications

Jeong, Chan Yang; Kubota, Takashi; Tajima, Kazuki

doi:10.1039/d1ra05280b

Cited by 18 publications

(11 citation statements)

References 51 publications

(67 reference statements)

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“…The EC materials are mainly categorised as inorganic or organic. Inorganic materials include transition metal oxides (e.g., tungsten oxide 8 , nickel oxide 9 ) and inorganic complexes (e.g., organic framework 10 ). Organic materials consist of π-conjugated organic molecules (e.g., viologen 11 ), conductive polymers (e.g., polyimide 12 , polythiophene 13 ), etc.…”

Section: Introductionmentioning

confidence: 99%

“…Our group has been developing inks based on aqueous dispersions of tungsten oxide (WO 3 ) and PB nanoparticles (NPs) for application in wet processes to prepare EC thin films 8 , 10 . Among wet processes, printing 19 and coating 20 , 21 offer the advantage of enabling EC thin film fabrication on large-scale substrates in a short time and at a low cost.…”

Section: Introductionmentioning

confidence: 99%

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Black electrochromic ink with a straightforward method using copper oxide nanoparticle suspension

Jeong

Watanabe

Tajima

2023

Sci Rep

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Electrochromic (EC) materials for smart windows must exhibit a dark colour and block visible light (wavelength = 380–780 nm) to reduce environmental impact. In particular, black tones are also desired, and there are many reports of attempts to create these dark tones using organic materials such as polymers. However, their fabrication methods are complicated, expensive, and may even use hazardous substances; moreover, they are often not sufficiently durable, such as upon exposure to ultraviolet light. There are some reported cases of black materials using the CuO system as an inorganic material, but the synthesis method was complicated and the functionality was not stable. We have found a method to synthesize CuO nanoparticles by simply heating basic copper carbonate and adjusting the pH with citric acid to easily obtain a suspension. The formation and functionality of CuO thin films were also demonstrated using the developed suspension. This research will enable the creation of EC smart windows using existing inorganic materials and methods, such as printing technology, and is the first step towards developing environment-friendly, cost-effective, and functional dark inorganic materials.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Black electrochromic ink with a straightforward method using copper oxide nanoparticle suspension

Jeong

Watanabe

Tajima

2023

Sci Rep

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“…Thus, in EC devices PB thin films are commonly switched between PB and PW. [21,22] PB thin films can be deposited via hydrothermal methods [23] or wet-chemical processes, such as electrodeposition, [24,25] spin coating, [26,27] inkjet printing, [28] or roll-to-roll slot-die coating. [14,15] Besides the application in EC devices, where PB is usually used as the anode material, it can be also considered as a cathode material for energy storage devices, e.g., sodium-ion batteries, [29,30] due to the similar working mechanisms to lithium-ion batteries.…”

Section: Introductionmentioning

confidence: 99%

Reflective and Complementary Transmissive All‐Printed Electrochromic Displays Based on Prussian Blue

et al. 2022

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By combining the electrochromic (EC) properties of Prussian blue (PB) and poly(3,4‐ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS), complementary EC displays manufactured by slot‐die coating and screen printing on flexible plastic substrates are reported. Various display designs have been realized, resulting in displays operating in either transmissive or reflective mode. For the transmission mode displays, the color contrast is enhanced by the complementary switching of the two EC electrodes PB and PEDOT:PSS. Both electrodes are either exhibiting a concurrent colorless or blue appearance. For the displays operating in reflection mode, a white opaque electrolyte is used in conjunction with the EC properties of PB, resulting in a display device switching between a fully white state and a blue‐colored state. The developments of the different device architectures, that either operate in reflection or transmission mode, demonstrate a scalable manufacturing approach of all‐printed EC displays that may be used in a large variety of Internet of Things applications.

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“…Mixed-valence compounds are promising for the application of smart windows and electrochromic display devices or sensors. − Prussian Blue (Fe 4 [Fe(CN) 6 ] 3 ) is well known as a mixed-valence hexacyanometalate and exhibits blue color due to intervalence charge transfer (IVCT) from Fe(II) to Fe(III). − A molar extinction coefficient of a soluble form as KFe[Fe(CN) 6 ] has been reported to be 8.4 × 10 3 dm 3 mol –1 cm –1 at 716 nm or 3.0 × 10 4 dm 3 mol –1 cm –1 at 700 nm . When phosphomolybdic anion (PMo 12 O 40 3– ), which is produced by the reaction of MoO 4 2– with PO 4 3– , is reduced by a reducing agent such as ascorbic acid, the color changes from yellow to blue owing to the IVCT transition from Mo(V) to Mo(VI).…”

Section: Introductionmentioning

confidence: 99%

Determination of W(V) in WO₃ Photochromism Using Localized Surface Plasmon Resonance of Ag Nanoparticles

Yamazaki

Isoyama

2022

J. Phys. Chem. B

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A reversible color change of WO3 has been widely studied to develop new energy-saving technologies such as smart windows, rewritable paper, and information displays. A blue coloration arises from the intervalence charge transfer between W(VI) and W(V), which is partially formed by the reduction of WO3 under UV light or an applied voltage. This means that WO3 has a mixed-valence state of W(V) and W(VI) upon the reduction. However, despite many studies for various applications, how many W(V) atoms are formed and contribute to the intervalence charge transfer (IVCT) transition remains unclear because W(V) formed in WO3 cannot be determined quantitatively. We determined the amount of the photogenerated W(V) in an aqueous WO3 colloidal solution containing ethylene glycol (EG) by observing the localized surface plasmon resonance (LSPR) peaks of Ag nanoparticles which were produced by a redox reaction between W(V) and Ag+. EG acted as a hole scavenger to suppress the recombination between the photogenerated holes and electrons. First, we explored the reaction condition where only the IVCT transition was observed under UV irradiation, and then it decreased in response to the increase in the LSPR peak in the dark. Under such a condition, the absorbance at 775 nm (A 775) due to the IVCT transition was observed after the UV irradiation for 30 s, and the absorbance at 410 nm (A 410) due to the LSPR absorption was obtained when A 775 completely disappeared in the dark. Experiments were performed at various UV intensities to confirm a proportional relationship between A 775 and A 410. Electron spin resonance measurements revealed that A 775 was proportional to the amount of W(V). Furthermore, Ag nanoparticles were synthesized by a polyol reduction method to obtain the relationship between the LSPR peak intensity and the Ag+ concentration, which was consumed for the formation of Ag. On the basis of all of these relationships, A 775 of 1.669 corresponded to 2.53 × 10–4 mol dm–3 W(V), which was estimated to be only 0.21% of 0.12 mol dm–3 WO3 used in this study, and the molar absorption coefficient for the IVCT transition between W(V) and W(VI) was evaluated to be 6.85 × 103 dm3 mol–1 cm–1.

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Flexible electrochromic devices based on tungsten oxide and Prussian blue nanoparticles for automobile applications

Abstract: Next-generation flexible ECD using nanoparticles water-dispersion ink.

Cited by 18 publications

References 51 publications

Black electrochromic ink with a straightforward method using copper oxide nanoparticle suspension

Black electrochromic ink with a straightforward method using copper oxide nanoparticle suspension

Reflective and Complementary Transmissive All‐Printed Electrochromic Displays Based on Prussian Blue

Determination of W(V) in WO₃ Photochromism Using Localized Surface Plasmon Resonance of Ag Nanoparticles

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Flexible electrochromic devices based on tungsten oxide and Prussian blue nanoparticles for automobile applications

Abstract: Next-generation flexible ECD using nanoparticles water-dispersion ink.

Cited by 18 publications

References 51 publications

Black electrochromic ink with a straightforward method using copper oxide nanoparticle suspension

Black electrochromic ink with a straightforward method using copper oxide nanoparticle suspension

Reflective and Complementary Transmissive All‐Printed Electrochromic Displays Based on Prussian Blue

Determination of W(V) in WO3 Photochromism Using Localized Surface Plasmon Resonance of Ag Nanoparticles

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Determination of W(V) in WO₃ Photochromism Using Localized Surface Plasmon Resonance of Ag Nanoparticles