小林 範久

我々は以前から有機トランジスタの誘電体層に合成タンパク質であるポリ(γ-メチルーL-グルタメート) [PMLG]の薄膜を用いると強誘電的なメモリ特性を示すということを報告してきた。このメモリ素子はフレキシブル基板上に印刷法で形成することが可能であるが、さらなる高性能化と大面積化を実現するためには製造プロセスに適合性のある要素技術を検討しておく必要がある。この素子はPMLG分子の配向状態と分子間相互作用をコントロールすることで良好なメモリ特性が得られることが分かっているが、最適な高次構造の特定には至っていない。そこで本報ではPMLGの3次構造の制御を行って、その電気特性を評価することでそれらの相関について検討を行い、印刷法に適合したデバイス作製の要素技術を開発し、高性能なメモリ素子を得ることを目的とした。

A Polyaniline (PAn)/ DNA complex has been successfully prepared by the photopolymerization of dimeric aniline via photocatalytic reaction of Ru(bpy)(3)(2+) in the presence of DNA. The reaction occurs even in the solution at pH 3.0 - 6.0, due to the specific local "lower-pH" environment provided by DNA. The PAn in the complex has ordered structure associated with double-helical DNA. The complex contains photocatalyst, Ru(bpy)(3)(2+), even after purification and the Ru(bpy)(3)(2+) also works as emitting material. A Ru(bpy)(3)(2+) Complex-based red-emitting diode with a fast turn-on response was successfully fabricated by employing this novel, processable and water-soluble PAn/DNA complex.

The under coated layer (UCL) in xerographic photoconductor has various functions so as to prevent charge injection from Al substrate to charge generation layer (CGL) and to remove charge accumulation on the CGL. Metal oxide particles are commonly used as UCL, but its properties are not enough. It is known that certain dyes are added to improve the properties of UCL. In this paper, the Thermally Stimulated Current of ZnO based film was studied from a view point of UCL. An effect of dye added in the film was also discussed.

DNA is expected to apply for organic EL devices and molecular wires. We studied the preparation and structure of DNA-PAn complex. It was revealed that PAn showed helical structure along with DNA main chain in the DNA-PAn complex. We applied this DNA/PAn complex as a material for OLED.

We studied electrochromic materials, which showed vivid color change to cyan, magenta or yellow upon electrochemical sutimulation, from a view point of electronic paper. In this paper, we designed color flexible electrochromic display with novel polymer electrolyte and studied their electrochromic characteristics.

We studied electrochromic materials, which showed reversible color change by electronic stimuli, from a view point of electronic paper. In this paper, we designed flexible electrochromic display with novel polymer electrolyte for color electronic paper and studied their electrochromic characteristics.

We have reported the preparation of polyaniline(PAn)/DNA complex by mixing PAn solution and DNA aqueous solution. We used chemically polymerized PAn with higher molar mass to produce PAn/DNA complex easier. The complex was soluble in aqueous solution although the PAn had emeraldine salt form. The structure of PAn/DNA complex was deeply affected by the preparation procedure. The effect of preparation procedure on the structure of PAn/DNA complex was discussed.

Space-selective electrochromic imaging was successfully performed with a novel polymer electrolyte composed of poly(vinylbutyral) (PVB), poly(ethyleneglycole) (PEG) and tetrabutylammonium perchlorate (TBAP). The spreading of the electrochromic image is a shortcoming when the image is space-selectively formed by electrochemical reaction. This is due to a cell formation between colored and uncolored parts through an ionic conductor. In order to inhibit the spreading, it would be effective to apply a polymer electrolyte with very low ionic conductivity at room temperature to the imaging system. Based on this, we designed the polymer electrolyte to have a large difference in ionic conductivity between high and low temperatures. This polymer electrolyte enables writing and erasing at a high temperature due to high ionic conductivity, and the image is to be preserved without change in ambient temperature due to very low ionic conductivity. In fact, space-selective image was successfully formed on the electrochromic device with the present polymer electrolyte at 100 degrees C, and was stable without change for more than a week when the device was kept at 20 degrees C. (c) 2005 Elsevier B.V. All rights reserved.

We studied organic electrochromic materials, which showed vivid color change to cyan, magenta or yellow upon electrochemical stimulation, from a view point of a new class of color electronic paper. Coloring and bleaching could be repeated without any decay over 500 cycles. Further, flexible electrochromic cell with gel polymer electrolyte has also been demonstrated.

The under coated layer (UCL) in xerographic photoconductor has various functions so as to prevent charge injection from Al substrate to charge generation layer (CGL) and to remove charge accumulation on the CGL. Metal oxide particles are commonly used as UCL, but its properties are not enough. It is known that certain dyes are added to improve the properties of UCL. In this paper, the electric properties of ZnO based film was studied from a view point of UCL. An effect of dye added in the film was also discussed.

DNA is expected to apply for organic EL devices and molecular wires. We can introduce functional materials such as charge transport materials and luminescence materials on DNA backbone since DNA has anionic groups on the side chain. We have already reported DNA EL device and its charge transport mechanism. In this research, we studied molecular alignment of DNA complex by means of ac field.

Electrochromic materials, which show reversible color change by electronic stimulation, have been attracting significant interest for potential uses in a paper-like electronic imaging device. We studied electrochemical properties of organic electrochromic materials, which showed vivid color change to cyan, magenta or yellow upon electrochemical stimulation, from a view point of a new class of color electronic paper.

We studied electrochemical properties of electrochromic materials, which showed reversible color change by electronic stimuli, from a view point of paper-like imaging device.

DNA is expected to apply for organic EL devices and molecular wires. We can introduce functional materials such as charge transport materials and luminescence materials on DNA backbone since DNA has anionic groups on the side chain. We have already reported DNA EL device and its charge transport mechanism. In this research, we studied molecular alignment of DNA complex by means of ac field.

Novel polymer electrolyte aimed for space-selective electrochromic imaging was prepared with poly(vinylbutyral) (PVB), poly(ethyleneglycole) (PEG2000) and tetrabutylammonium perchlorate (TBAP). A spreading of the electrochromic image is a shortcoming when the electrochromic image is space-selectively formed by electrochemical reaction. This is due to a cell formation between colored and uncolored parts through ionic conductor. In order to inhibit the spreading, it would be effective to apply a polymer electrolyte with very low ionic conductivity at room temperature to the imaging system. On this basis, the present electrolyte was designed to have large difference in ionic conductivity between high and low temperatures. Namely, this polymer electrolyte enables writing and erasing at high temperature due to high ionic conductivity, and the image is expected to be preserved without change at ambient temperature due to very low ionic conductivity. The thermal and conductive properties of the polymer electrolyte were analyzed. Further, space-selective electrochromic image was formed on the device with the present polymer electrolyte at 100 degrees C, and was revealed to be stable without change for more than a week when the device was kept at 20 degrees C. (c) 2005 Elsevier Ltd. All rights reserved.

Photoluminescence (PL) and Electroluminescence (EL) abilities of 9,10-bis(silylethynyl)antheacene were investigated. Fluorescence quantum yield of these compounds increased drastically and reached nearly unity by the substitution of silylethynyl groups for 9, 10-position of anthracene. EL devices made of 9,10-bis triphyenylsilylethynyl)anthracene showed greenish yellow EL, and the use of PEDOT/PSS and Alq(3) improves the performance of the device.

We studied electrochemical properties of electrochromic materials, which showed reversible color change by electronic stimuli, from a view point of paper-like electronic imaging device. Electrochemical materials showing color changes from clear to the three primary colors such as RGB or CMY should be required to realize full color paper-like electronic imaging decvice. In this paper, we studied electrochromic characteristics of phthalate derivatives from the view point of its color and the electrochromic mechanism for paper-like display.

We studied electrochemical properties of electrochromic materials, which showed reversible color change by electronic stimuli, from a view point of paper-like electronic imaging device. Electrochemical materials showing color changes from clear to the three primary colors such as RGB or CMY should be required to realize full color paper-like electronic imaging decvice. In this paper, we studied electrochromic characteristics of viologen and phthalate derivatives from the view point of its color and the electrochromic mechanism for paper-like display.

Polyaniline (PAn) has been successfully prepared by photopolymerization of dimeric aniline via photocatalytic reaction with Ru (bpy) <SUB>3</SUB><SUP>2+</SUP>. We investigated template photopolymerization in the presence of DNA in order to prepare PAn with longer π-conjugation length. The PAn/DNA complex formed in an aqueous solution was water-soluble, leading to improve the processability of PAn for devices. The PAn/DNA complex film containing Ru (bpy) <SUB>3</SUB><SUP>2+</SUP> shows red light emission by applying a voltage. The device, <I>i.e</I>., Al/PAn-DNA complex+Ru (bpy) <SUB>3</SUB><SUB>2+</SUB>/ITO, emitted light over a bias voltage of 7 V, and the luminance increased with increasing bias voltage. A maximum luminance of 1500 cd/m<SUP>2</SUP> was observed.

Synthetic polypeptides with rigid α-helical structure are regarded as promising materials for molecularly ordered membrane with high charge or energy transport properties. We prepared Ru (bpy) <SUB>3</SUB><SUP>2+</SUP>/α-helical poly (L-glutamic acid) (PGA) complex to study charge transport properties and its application to optoelectric devices. Substitution ratio of long alkyl chain group and polypeptide secondary structures were characterized by <SUP>1</SUP>H-NMR and IR spectra. The interaction between PGA and Ru (bpy) <SUB>3</SUB><SUP>2+</SUP> was analyzed with CD and fluorescence spectroscopy. The structure of PGA/Ru (bpy) <SUB>3</SUB><SUP>2+</SUP> complex was estimated. Further, we prepared EL device with PGA/ Ru (bpy) <SUB>3</SUB><SUP>2+</SUP> complex to discuss the emission mechanism.

電気的な刺激で可逆的な色変化を示すエレクトロクロミック材料は電子ペーパー等新規な表示デバイス用の材料として注目を集めている．これまで多くの研究が，たとえば有機系においてはビオローゲン誘導体やPEDOTをはじめとする導電性高分子に対して行われてきたが，発現できる色に制限があった．フルカラーの電子ペーパーを実現するためには無色透明状態からRGBやCMYの3原色に可逆的に発消色できるエレクトロクロミック材料が必要である．本稿ではまず最初にフルカラー電子ペーパー実現の観点からテレフタル酸誘導体が示すエレクトロクロミック特性やそれを用いたエレクロトクロミックセルの特性について解説する．さらには，最近のエレクトロクロミックディスプレイの技術展開についても紹介する．

DNA-Ru(bpy)(3)(2+) complex was prepared to study EL characteristics. Ru(bpy)(3)(2+) was associated with duplex of DNA by the interaction such as intercalation in the pH 3 aqueous solution. It was revealed that the EL device composed of DNA-R(bpy)(3)(2+) complex exhibited extremely faster response than the other Ru(bpy)(3)(2+) based EL devices. The emission mechanism was discussed. DNA-Ru(bpy)(3)(2+) complex is expected to be applicable to an optoelectro-functional molecular wire.

Novel carbazole-containing polymers, i.e., poly(3,6-di-tert-butyl-N-(p-ethynylphenyl)carbazole) [poly(t-Bu(2)CzPA)] and poly(N-(p-ethynylbenzoyl)carbazole) [poly(CzCOPA)] were synthesized by the polymerization of the corresponding carbazole-containing acetylene monomers using [(norbornadiene)-RhCl](2)-Et3N, WCl6-n-Bu4Sn, and WCl4 catalysts. The UV-vis absorption band edge wavelengths of the polymers obtained by the polymerization with W catalysts were longer than those of the Rh-based polymers. The photoluminescence quantum yield of the W-based poly(t-Bu(2)CzPA) was 55%, while that of the Rh-based one was as low as 3.6%. The photocurrent of poly(t-Bu(2)CzPA) was 40-50 times higher than the dark current. Poly(t-Bu2CzPA) in conjunction with iridium complexes exhibited electroluminescence (13-18 cd/m(2)).

Electrochemical and spectroscopic measurements with CV, chronoamperometry and in situ spectrometry were carried out for dimethyl terephthalate, which showed vivid color change upon electrochemical stimulation, to clarify its electrochromic characteristics.

Recently, the demand for global environmental conservation and decrease of CO<SUB>2</SUB> evolution require the development of “new imaging media” instead of paper. This is called “electronic paper”, and many candidates have been reported to realize this new media. In this paper, some recent aspects of electronic paper will be reviewed.

α-Helical poly (γ-16-alkyl-L-glutamate) (PG16) and poly (γ-(2-9-carbazolyl) ethyl)-L-glutamate (PCLG) were prepared to study charge transport properties in PCLG/PG16 blend. Substitution ratio of long alkyl chain group and polypeptide secondary structures were characterized by 11-I-NMR and IR spectra. Thermal properties of the blend indicated that some part of PCLG and PG16 were solubilized each other in the blend and that the blend showed liquid crystalline behavior above 50°C. The contact poling was carried out by the application of 600V to the film at 70°C for 3 hours. I-V characteristics of PCLG/PG16 film were improved by the poling. These results were discussed with the orientation of PCLG molecules.

生命現象の中心的な存在として広く知られるDNAは,生命情報を保存・伝達できる天然の機能性高分子である。構造的な特徴や生体的な刺激応答性は良く知られているが,コンピューティングや分子導線ワイヤーとして利用できるのではという報告以来,光や電子機能を示す材料への展開や,素子化が試みられている。ここでは,DNAの特徴を生かした光電機能材料の設計と,光電機能素子への展開について最近の話題を紹介する。

Polypeptidc having carbazolyl groups (poly(-gamma-[2-(9-carbazolyl)ethyl]-L-glutamate) (PCLG)) was synthesized in order to prepare a lyotropic liquid crystalline cell with higher mobility. This liquid crystal was revealed to show d.c. electric-field induced scattering behavior, in which the transparent cell became scattered after applying d.c. bias voltage. This behavior was enhanced by adding small amounts of 24,17-trinitro-fluorenone (TNF) which is known to form charge transfer complex with carbazole. The transmittance varied from 90 to 20% under d.c. bias application. More than 150 turn-on and off cycles were achieved in this cell without serious degradation. Copyright (C) 2003 John Wiley Sons, Ltd.

Novel polymer electrolyte aimed for electrochromic display was prepared by polyvinylbutyral (PVB), imidazole (Imz) and tetrabutylammonium perchlorate (TBAP). The polymer electrolyte was designed to have large difference in ionic conductivity between high and low temperature. This would be effective to inhibit the spreading of electrochromic images at ambient temperature due to cell formation between colored and uncolored parts through ionic conductor. Namely, this polymer electrolyte enables writing and erasing at high temperature due to high ionic conductivity, and the image is expected to be preserved without change and spreading at ambient temperature due to low ionic conductivity. In the results, the ionic conductivity in the polymer electrolyte was dramatically increased above the quasi-melting point of the component. Optimum ratio between Imz and TBAP content should be required to obtain higher ionic conductivity at high temperature. Ionic conductive properties of the polymer electrolyte were mainly studied and discussed. (C) 2003 Elsevier Science Ltd. All rights reserved.