Vertical orientation with a narrow distribution of helical peptides immobilized on a quartz substrate by stereocomplex formation

Second-harmonic generation (SHG) of a donor–π–acceptor (D–π–A) chromophore attached to helical peptides was used for the evaluation of the self-assembled monolayer (SAM) structure of a stereocomplex of helical peptides. A stereocomplex SAM of a left-handed helical conjugate (D17) and a right-handed helical conjugate (L17) showed an SHG intensity four times larger than a stereocomplex SAM of a left-handed helical D17 and a right-handed helical peptide without the D–π–A chromophore (LA16), which agrees well with dependence of SHG intensities on the surface densities of the D–π–A chromophore. The SHG intensities of enantiopure SAMs of D17 and L17 are, however, 47% and 27% of the stereocomplex SAM of D17 and L17, respectively. These differences can be explained only after taking a larger distribution of the tilt angle of the chromophore in the enantiopure SAMs than in the stereocomplex SAM of D17 and L17. On the basis of these analyses, it is concluded that the stereocomplex SAM of a left-handed helix and a right-handed helix constitutes a well-ordered structure, where the tilt angle of the helical peptide from the surface normal becomes small with a narrow distribution due to stereocomplex formation

Probing of Transient Electric Field Distribution in ITO/PI/P3HT/Au By Time-Resolved Optical Second Harmonic Generation Measurement

AbstractBy using time-resolved optical second harmonic generation (TR-SHG) measurements, we studied carrier behaviors in poly(3-hexylthiophene) (P3HT) metal-insulator-semiconductor (MIS) diodes. TR-SHG measurements probed transients of electric fielddistribution in the P3HT active layer. Results showed that hole injection and removal processes were non-reversal, where the response times were different from each other and the relaxation time of the transient electric field strongly depended on the hole injection process

Probing and Analysis of the deformation of two-dimensional domain shape

この論文は国立情報学研究所の電子図書館事業により電子化されました。研究会報告水面上に形成された単分子膜は、表面圧に応じて様々な相を呈する。そこで、筆者らは誘電物性評価の立場から界面膜の誘電分極構造、すなわち、自発分極、線形非線形分極を、マックスウェル変位電流ブリュスター角顕微鏡、光第2次高調波により測定する技術開発を進め、その測定に成功した。また、この実験結果を基礎と、界面膜の2次元ドメイン形成に、双極子エネルギーが大きく寄与していることに着目しながら界面のドメイン形状を決定するshape equationの導出もしてきた。本報告では界面膜の分極構造の実験的評価とドメイン形状の理論について紹介し、これらの知見がソフトな材料の新しい物性を見出すのに役立つことを述べる

Electrostatic Analysis of Chiral Phase Separation in a Dipolar Monolayer Domain : Perturbation Analysis(Poster session 1, New Frontiers in Colloidal Physics : A Bridge between Micro- and Macroscopic Concepts in Soft Matter)

この論文は国立情報学研究所の電子図書館事業により電子化されました。電気四重極子密度と自発分極との相互作用がドメイン形状の形成に重要な寄与をすることを発見したことから、リン脂質のラセミ混合膜が液相-凝縮相の共存領域で形成するドメインの形状の形成原因を明らかにするために、単分子膜から発生する自発分極と電気四重極子密度を考慮に入れて、静電的なモデルを構築した。トルクバランス方程式と化学ポテンシャルの釣り合いの式から、ラセミ混合膜は、単分子膜の圧縮中に、ドメインの内部でキラル相分離を起こす可能性を見出した

Nano-interface Surface Dielectric Polarization Phenomena: Detection and Application

Nano-interfacial dielectric polarization phenomena were discussed from the viewpoint of electronics, paying attention to the alignment of dipoles and dipolar energy. Firstly, we summarized dielectric polarization phenomena of monolayer comprised of polar molecules, and showed that monolayer is quite different from bulk materials, and the unique dielectric properties of monolayers can be discussed in terms of orientational order parameters. Maxwell-displacement-current (MDC) measurement coupled with optical second harmonic generation (SHG) measurement is shown as an effective way for detecting unique dielectric polarization phenomena of surface monolayers. Then, the importance of dielectric energy is discussed from the viewpoint of monolayer pattern formation and pointed out that the control of dipolar energy can be new pattern formation technology

Electron-blocking hole-transport polyterpenol thin films

The carrier blocking property of polyterpenol thin films derived from non-synthetic precursor is studied using Electric Field Induced Optical Second Harmonic Generation (EFISHG) technique that can directly probe carrier motion in organic materials. A properly biased double-layer MIM device with a structure of indium zinc oxide (IZO)/polyterpenol/C₆₀/Al shows that by incorporating the polyterpenol thin film, the electron transport can be blocked while the hole transport is allowed. The inherent electron blocking hole transport property is verified using Al/C₆₀/Alq3/polyterpenol/IZO and Al/Alq3/polyterpenol/IZO structures. The rectifying property of polyterpenol is very promising and can be utilized in the fabrication of many organic devices

Spontaneous Splay of Monolayers Comprised of Chiral Molecules at the Air-Water Interface Due to the Electric Quadrupole Effect

この論文は国立情報学研究所の電子図書館事業により電子化されました。研究会報告シリンダーモデルを用いて、棒状キラル分子によって構成される水面上単分子膜から発生する自発四重極子モーメント密度を解析した。電気四重極子モーメント密度が発生するためには、分子長軸方向の秩序がなくてはならないことを示した。電気四重極子モーメント密度によって生じる静電エネルギーの解析によって、電気四重極子モーメント密度が単分子膜の自発スプレーの原因になることを示した

OrientationalOrdering Process of Liquid Crystalline Molecules Evaporated on Azobenzene Monolayer: Optical Polarized Absorption Measurements and Adsorption Kinetics

The orientational order of 4-n-pentyl-4\u27-cyanobiphenyl (5CB) molecules deposited on silica substrates coated with trans-form azobenzene monolayer was examined during deposition, in-situ, using optical polarized absorption measurements. It was revealed that the orientational order change was induced by monolayer formation, due to the change of adsorption kinetic