Fused-Fluoran Leuco Dyes with Large Color-Change Derived from Two-Step Equilibrium: <i>iso</i>-Aminobenzopyranoxanthenes

Shirasaki, Yoshinao; Okamoto, Yoshiki; Muranaka, Atsuya; Kamino, Shinichiro; Sawada, Daisuke; Hashizume, Daisuke; Uchiyama, Masanobu

doi:10.1021/acs.joc.6b02403

Cited by 27 publications

(14 citation statements)

References 39 publications

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“…In the course of our studies on the creation of new functional materials based on fluoran leuco dyes, we unexpectedly observed the formation of 1 Hex . When iso -aminobenzopyranoxanthene ( iso -ABPX) was synthesized from 2-(4-dihexylamino-2-hydroxybenzoyl)benzoic acid and hydroquinone using concentrated sulfuric acid as a solvent, a trace amount of 1 Hex was detected by MALDI-TOF-MS. With the aim of improving the product yield, the reaction conditions were optimized using iso -ABPX as a starting material and yields of up to 17% were achieved (Schemes a and S1).…”

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confidence: 92%

Stable Thiele’s Hydrocarbon Derivatives Exhibiting Near-Infrared Absorption/Emission and Two-Step Electrochromism

et al. 2018

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We report synthesis and characterization of near-infrared (NIR)-absorbing/emitting Thiele's hydrocarbon derivatives, in which four aryl groups are bridged to a quinodimethane skeleton. The quinoid structure of the bridged-tetra-aryl-p-quinodimethanes (BTAQs) was confirmed by spectroscopic, X-ray crystallographic, and computational methods. Although quinodimethane derivatives with a small HOMO−LUMO energy gap often exhibit biradical character, BTAQs showed no biradical character. Instead, they exhibited two-step near-infrared electrochromism. The donor/acceptor properties of the aryl groups were found to play a key role in the unique properties of BTAQs.

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confidence: 92%

Stable Thiele’s Hydrocarbon Derivatives Exhibiting Near-Infrared Absorption/Emission and Two-Step Electrochromism

et al. 2018

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“…Normally, 2‐ethoxyethanol is also known as one of the alkoxy ethanol solvents due to the presence of oxygen (‐O‐) and hydroxyl (‐OH‐) group in the same molecule . This hydroxyl group in 2‐ethoxyethanol can provide additional protons, which moves the equilibrium state of EC dye to the lactone‐ring opening state, resulting in significantly enhanced optical characteristics . Furthermore, 2‐ethoxyethanol has been widely studied in the electrochemistry field such as fuel cell or battery owing to its ion conductivity …”

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confidence: 99%

High‐Performance Reflective Electrochromic Device by Integrating White Reflector and High Optical Density Electrochromic System

Park

Kim

et al. 2019

Adv Materials Inter

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white color. To improve these optical characteristics, a wide aperture ratio and high reflection with excellent light blocking approach are highly essential.Previously, several approaches (electrophoretic, electrowetting, cholesteric liquid crystal, and electrochromic device (ECD)) have been reported as the most possible solution for reflective display applications. In particular, electrophoretic [13][14][15] and electrowetting [16][17][18] can control the intensity of reflected light by changing an area of the absorber inside the pixel. Despite paper-level readability and fast response time, their driving mechanism decreases the ACR owing to less amount of available light by limited aperture ratio. On the other hand, cholesteric liquid crystal [19][20][21] and ECD [22][23][24] can control the intensity of light via mana ging the absorbance according to the state of the transparent molecules in the complete pixel area. Although cholesteric liquid crystal has merits in terms of realizing full color and good optical control ability, it utilizes polarizer that can cause substantial optical loss. [25] Besides, only filtered light can pass through the polarizer and that consequently leads to a poor reflectivity in the white state. In contrast, ECD can easily control the reflection of light by altering the absorbance property according to the redox state of the electrochromic (EC) dye. Moreover, ECD does not require the use of a polarizer, thus, theoretically almost complete ambient light can be utilized without any optical loss. This device also possesses a high aperture ratio, high transmittance, and excellent light shutter effect. Therefore, ECD is the most favorable candidate for reflective display applications.In this paper, we demonstrate an efficient reflective ECD with a very high ACR and excellent driving stability. The fabricated reflective ECD by incorporating micro-porous titanium dioxide (TiO 2 )-based white reflector film and well-optimized EC composition revealed not only a deep black state (1.7 V) and white state (0.0 V) due to the good optical density of the EC dye but also excellent reflectivity of about 58.5% at 550 nm. Prior to the fabrication of reflective ECD, EC composition was optimized by selecting suitable proton donor, solvent, and supporting polymer to attain good coloration property, low driving voltage, and high optical density with the faster response time.This paper reports an efficient reflective electrochromic device (ECD) by integrating a highly reflective micro-porous titanium dioxide-based white reflector film and an optimized transparent to black convertible electrochromic (EC) system. This reflective ECD can reflect almost 58.5% of light in the white state and 4.7% in the dark black state at 550 nm. Similarly, it also exhibits a very high ambient contrast ratio of 38:1 under office ambient light condition and good driving stability of about 83% in the white state (0 V) and 98% in the black state (1.7 V) after 10 000 driving cycles. In addition, the EC system is optimized by select...

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“…The difference between the color coordinates of the green-and blue-colored TCECFs and CFs was very small, however, and the optical characteristic of the blue TCECF was still lower than that of the blue CF despite its excellent transmittance in the bleached state. Indeed, it is expected to have an improved color gamut in the TCECF-based full-color reflective display by enhancing the optical properties of the blue TCECF with a suitable solvent and stabilizer for enhanced ionic-state stability [27,28]. In addition, the full-color reflective display with TCECF is more suitable for providing various colors with high brightness and saturation with a broad grayscale because of its clear white color in the off-state of both the reflective ECD and TCECF compared to that of CF.…”

Section: Resultsmentioning

confidence: 99%

An optically efficient full-color reflective display with an electrochromic device and color production units

Park

Kim

et al. 2019

Journal of Information Display

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In this paper, we report a full-color reflective display device by combining reflective electrochromic device (ECD) and different color production units (conventional color filter (CF) and transmittance controllable electrochromic color filter (TCECF)). A full-color reflective device with TCECF showed an excellent diffuse reflectance of 47.2% in the white state owing to the high transmittance of TCECF in the bleached state than that of CF (19.5%). This device structure can easily provide various colors with high brightness and saturation with a broad grayscale. Particularly, in the colored state, TCECF and CF-based full-color reflective device displayed color coordinates of (0.59, 0.34), (0.31, 0.66), (0.24, 0.30) and (0.65, 0.33), (0.27, 0.61), (0.15, 0.06), for red, green and blue, respectively, and alongside also exhibited color gamut of 36.8% (for TCECF) and 73.1% (for CF) for full color reflective devices.ARTICLE HISTORY His research interests include the development of new organic materials for optoelectronic devices including OLEDs, QD-LEDs, OPV, and electrochromic devices. He has authored/co-authored over 145 SCI-indexed papers and also has about 98 registered patents (national and international).

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Fused-Fluoran Leuco Dyes with Large Color-Change Derived from Two-Step Equilibrium: iso-Aminobenzopyranoxanthenes

Cited by 27 publications

References 39 publications

Stable Thiele’s Hydrocarbon Derivatives Exhibiting Near-Infrared Absorption/Emission and Two-Step Electrochromism

Stable Thiele’s Hydrocarbon Derivatives Exhibiting Near-Infrared Absorption/Emission and Two-Step Electrochromism

High‐Performance Reflective Electrochromic Device by Integrating White Reflector and High Optical Density Electrochromic System

An optically efficient full-color reflective display with an electrochromic device and color production units

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