The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Koji Suzuki - One of the best experts on this subject based on the ideXlab platform.
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bright color tunable Fluorescent Dyes in the vis nir region establishment of new tailor made multicolor fluorophores based on borondipyrromethene
Chemistry: A European Journal, 2009Co-Authors: Keitaro Umezawa, Yuki Nakamura, Daniel Citterio, Akihiro Matsui, Koji SuzukiAbstract:A new series of high-performance fluorophores named Keio Fluors (KFL), which are based on borondipyrromethene (BODIPY), are reported. The KFL Dyes cover a wide spectral range from the yellow (547 nm) to the near-infrared (NIR, 738 nm) region, and their emission wavelength could be easily and subtly controlled based on simple molecular modifications only, without losing their optical properties. This “tailor-made” synthetic strategy for tuning the emission wavelength enabled the creation of fourteen KFL Dyes with well-controlled emission colors (yellow, orange, red, far-red, and NIR). Moreover, these KFL Dyes also retain their excellent optical properties, such as spectral bands sharper than quantum dots, high extinction coefficients (140 000–316 000 M−1 cm−1), and high quantum yields (0.56–0.98), without any critical solvent polarity dependent decrease of their brightness. These advantageous characteristics make the KFL Dyes potentially useful as new candidates of Fluorescent standard Dyes to substitute or to complement existing long-wavelength Fluorescent Dyes, such as cyanines, oxazines, rhodamines, or other BODIPY Dyes.
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bright color tunable Fluorescent Dyes in the visible near infrared region
Journal of the American Chemical Society, 2008Co-Authors: Keitaro Umezawa, Hiroshi Makino, Yuki Nakamura, Daniel Citterio, Koji SuzukiAbstract:The newly synthesized Keio Fluors, which are based on boron-dipyrromethene (BDP), have excellent and useful optical properties: vivid colors and sharp emission in the visible−near-infrared region (583−738 nm), high quantum yields (Φ: 0.56−0.98), high extinction coefficients (185000−288000 M-1 cm-1), and good photostabilities. These optical properties are superior to many of the existing Fluorescent Dyes such as rhodamines, cyanines, or other BDP-based Fluorescent Dyes.
Katsutoshi Nagai - One of the best experts on this subject based on the ideXlab platform.
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single layer white light emitting organic electroluminescent devices based on dye dispersed poly n vinylcarbazole
Applied Physics Letters, 1995Co-Authors: Junji Kido, H Shionoya, Katsutoshi NagaiAbstract:Bright single‐layer white light‐emitting organic electroluminescent devices were developed by using dye‐dispersed poly(N‐vinylcarbazole) (PVK). The active layer consists only of one polymer layer that is simply sandwiched between two electrodes, indium‐tin oxide, and Mg:Ag. In order to achieve bipolarity in the single polymer emitter layer, PVK was molecularly dispersed with electron‐transporting additives such as 2‐(4‐biphenyl)‐5‐(4‐tert‐butylphenyl)‐1,3,4‐oxadiazole. In addition, several Fluorescent Dyes, having different emission colors, were dispersed as emitting centers. By adjusting the concentration of the Fluorescent Dyes, white light with a maximum luminescence of 4100 cd/m2 was obtained, which is the brightest white light ever observed for organic electroluminescent devices.
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white light emitting organic electroluminescent devices using the poly n vinylcarbazole emitter layer doped with three Fluorescent Dyes
Applied Physics Letters, 1994Co-Authors: Junji Kido, Kenichi Hongawa, Katsuro Okuyama, Katsutoshi NagaiAbstract:White light‐emitting electroluminescent devices were fabricated using poly(N‐vinylcarbazole) (PVK) as a hole‐transporting emitter layer and a double layer of 1,2,4‐triazole derivative (TAZ) and tris(8‐quinolinolato)aluminum(III) complex (Alq) as an electron transport layer. The PVK layer was doped with Fluorescent Dyes such as blue‐emitting 1,1,4,4‐tetraphenyl‐1,3‐butadiene, green‐emitting coumarin 6, and orange‐emitting DCM 1. A cell structure of glass substrate/indium‐tin‐oxide/doped PVK/TAZ/Alq/Mg:Ag was employed. White emission covering a wide range of the visible region and a high luminance of 3400 cd/m2 were obtained at a drive voltage of 14 V.
Junji Kido - One of the best experts on this subject based on the ideXlab platform.
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solution processable organic Fluorescent Dyes for multicolor emission in organic light emitting diodes
Journal of Materials Chemistry, 2008Co-Authors: Makoto Higashidate, Kenichi Nakayama, Junji KidoAbstract:Four novel Fluorescent Dyes, bis(difluorenyl)amino-substituted carbazole 1, pyrene 2, perylene 3, and benzothiadiazole 4, were synthesized by C–N cross-coupling with a palladium catalyst. These Dyes are soluble in common organic solvents, and their uniform films were formed by spin-coating from their solutions. Their glass transition temperatures were sufficiently high (120–181 °C) to form amorphous films for organic light emitting diodes. These solution processable Dyes exhibited strong photoluminescence (PL) in the film form (1: sky blue, 2: blue-green, 3: yellow, and 4: deep red). Optical and electrochemical properties of the compounds were investigated with photoelectron spectroscopy and cyclic voltammetry. The energy levels obtained from both measurements were in good agreement, and those levels were related to the electronic properties of the central core; the electron-donating carbazole compound showed the lowest ionization potential and the electron-withdrawing benzothiadiazole compound showed the largest electron affinity. Simple double layer devices were prepared with these Fluorescent Dyes as emitting layer and bis(2-methyl-8-quinolinolato)(4-phenylphenolato)aluminium(III) (BAlq) as a common hole blocking layer for each color. Electroluminescence colors were the same as those of the PL spectra in each compound. These multicolor electroluminescences show that these conjugated oligomers can be candidates for solution processable light emitting materials for OLEDs as well as conjugated polymers or dendrimers.
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single layer white light emitting organic electroluminescent devices based on dye dispersed poly n vinylcarbazole
Applied Physics Letters, 1995Co-Authors: Junji Kido, H Shionoya, Katsutoshi NagaiAbstract:Bright single‐layer white light‐emitting organic electroluminescent devices were developed by using dye‐dispersed poly(N‐vinylcarbazole) (PVK). The active layer consists only of one polymer layer that is simply sandwiched between two electrodes, indium‐tin oxide, and Mg:Ag. In order to achieve bipolarity in the single polymer emitter layer, PVK was molecularly dispersed with electron‐transporting additives such as 2‐(4‐biphenyl)‐5‐(4‐tert‐butylphenyl)‐1,3,4‐oxadiazole. In addition, several Fluorescent Dyes, having different emission colors, were dispersed as emitting centers. By adjusting the concentration of the Fluorescent Dyes, white light with a maximum luminescence of 4100 cd/m2 was obtained, which is the brightest white light ever observed for organic electroluminescent devices.
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white light emitting organic electroluminescent devices using the poly n vinylcarbazole emitter layer doped with three Fluorescent Dyes
Applied Physics Letters, 1994Co-Authors: Junji Kido, Kenichi Hongawa, Katsuro Okuyama, Katsutoshi NagaiAbstract:White light‐emitting electroluminescent devices were fabricated using poly(N‐vinylcarbazole) (PVK) as a hole‐transporting emitter layer and a double layer of 1,2,4‐triazole derivative (TAZ) and tris(8‐quinolinolato)aluminum(III) complex (Alq) as an electron transport layer. The PVK layer was doped with Fluorescent Dyes such as blue‐emitting 1,1,4,4‐tetraphenyl‐1,3‐butadiene, green‐emitting coumarin 6, and orange‐emitting DCM 1. A cell structure of glass substrate/indium‐tin‐oxide/doped PVK/TAZ/Alq/Mg:Ag was employed. White emission covering a wide range of the visible region and a high luminance of 3400 cd/m2 were obtained at a drive voltage of 14 V.
Keitaro Umezawa - One of the best experts on this subject based on the ideXlab platform.
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bright color tunable Fluorescent Dyes in the vis nir region establishment of new tailor made multicolor fluorophores based on borondipyrromethene
Chemistry: A European Journal, 2009Co-Authors: Keitaro Umezawa, Yuki Nakamura, Daniel Citterio, Akihiro Matsui, Koji SuzukiAbstract:A new series of high-performance fluorophores named Keio Fluors (KFL), which are based on borondipyrromethene (BODIPY), are reported. The KFL Dyes cover a wide spectral range from the yellow (547 nm) to the near-infrared (NIR, 738 nm) region, and their emission wavelength could be easily and subtly controlled based on simple molecular modifications only, without losing their optical properties. This “tailor-made” synthetic strategy for tuning the emission wavelength enabled the creation of fourteen KFL Dyes with well-controlled emission colors (yellow, orange, red, far-red, and NIR). Moreover, these KFL Dyes also retain their excellent optical properties, such as spectral bands sharper than quantum dots, high extinction coefficients (140 000–316 000 M−1 cm−1), and high quantum yields (0.56–0.98), without any critical solvent polarity dependent decrease of their brightness. These advantageous characteristics make the KFL Dyes potentially useful as new candidates of Fluorescent standard Dyes to substitute or to complement existing long-wavelength Fluorescent Dyes, such as cyanines, oxazines, rhodamines, or other BODIPY Dyes.
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bright color tunable Fluorescent Dyes in the visible near infrared region
Journal of the American Chemical Society, 2008Co-Authors: Keitaro Umezawa, Hiroshi Makino, Yuki Nakamura, Daniel Citterio, Koji SuzukiAbstract:The newly synthesized Keio Fluors, which are based on boron-dipyrromethene (BDP), have excellent and useful optical properties: vivid colors and sharp emission in the visible−near-infrared region (583−738 nm), high quantum yields (Φ: 0.56−0.98), high extinction coefficients (185000−288000 M-1 cm-1), and good photostabilities. These optical properties are superior to many of the existing Fluorescent Dyes such as rhodamines, cyanines, or other BDP-based Fluorescent Dyes.
Pengfei Wang - One of the best experts on this subject based on the ideXlab platform.
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deep red emissive crescent shaped Fluorescent Dyes substituent effect on live cell imaging
ACS Applied Materials & Interfaces, 2015Co-Authors: Weimin Liu, Bingjiang Zhou, Guangle Niu, Hongyan Zhang, Pengfei WangAbstract:A series of crescent-shaped Fluorescent Dyes (CP1-CP6) were synthesized by hybridizing coumarin and pyronin moieties with different amino substituents at both ends. The molecular structures and photophysical properties of these Fluorescent Dyes were investigated through X-ray diffraction, absorption spectroscopy, and fluorescence spectroscopy. Results show that the Fluorescent Dyes exhibited crescent-shaped structures, deep-red emissions (approximately 650 nm), and significant Stokes shifts. In live-cell-imaging experiments, CP1 stains mitochondria, whereas CP3 and CP6 stain the lysosomes in a cytoplasm and the RNA in nucleoli. The relationships between different amino substituent groups and the imaging properties of CP Dyes were discussed as well. Additionally, findings from the cytotoxicity and photostability experiments on living cells indicated the favorable biocompatibility and high photostability of the CP Dyes.
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coumarin and rhodamine fused deep red Fluorescent Dyes synthesis photophysical properties and bioimaging in vitro
Journal of Organic Chemistry, 2013Co-Authors: Jianhong Chen, Weimin Liu, Bingjiang Zhou, Guangle Niu, Hongyan Zhang, Ying Wang, Pengfei WangAbstract:A series of deep red Fluorescent Dyes (CR1 to CR3) was developed via introduction of a coumarin moiety into the rhodamine molecular skeleton. The novel Dyes possessed the individual advantages of coumarin and rhodamine derivatives, and the emission wavelength was extended to the deep red region (>650 nm) due to the extension of fused-ring conjugate structure simultaneously. To illustrate its value, we designed and conveniently synthesized a series of novel deep red bioimaging Dyes (CR1E to CR3E) by esterification of CR1 to CR3, which could selectively stain mitochondria. They were superior to the MitoTrackers for mitochondrial staining in terms of large Stokes shift, excellent contrast for imaging, high photostability, and low cytotoxicity. Furthermore, the fluorescence of the coumarin moiety and rhodamine-like fluorophore could be switched like classical rhodamine. Thus, they could be used as an effective platform in constructing fluorescence sensors. Based on this fact, we constructed a novel ratiometri...