Hidetsugu Ikeda

Nonlinear optical properties of cyanine dyes

Abstract Cyanine dyes, which consist of nitrogen heterocycles and a barbituric moiety on the opposite side of molecules, were synthesized and their second-order nonlinear optical properties were investigated by using the electric-field-induced second-harmonic-generation method. They were found to have very large molecular hyperpolarizabilities.

17.1: Invited Paper: Improvement of Lifetime in Organic Electroluminescence

Excellent organic electroluminescent materials are needed to realize EL devices with high performance. We have succeeded in realizing bright and efficient devices with long lifetime in blue color region by the use of a new host material. The lifetime was estimated to be 21000 hr (@1000 cd/m2) for the light blue devices. Furthermore, we achieved the long lifetime of 40000 hr (@1000 cd/m2) in green region.

Dependence of the spectrum and decay of transient photoinduced reflectance change on excitation wavelength and intensity in polydiacetylene single crystals

Abstract Transient reflectance changes in a polydiacetylene-toluene-sulfonate (PDA-TS) single crystal were found to be induced by pulsed excitations at 2.33 eV (532 nm), 3.49 eV (355 nm), and 4.66 eV (266 nm). The negative reflectance change around 1.4 eV, observed only by excitations at 4.66 and 3.49 eV was attributed to the lowest excited triplet state formed by the recombination of charge carriers.

Second harmonic generation in nonbenzenoid aromatics

Abstract Pentafulvene derivatives were synthesized and their second-order nonlinear optical properties were investigated by electric-field-induced second harmonic generation (EFISH) method. The pentafulvene group was found to act as a strong acceptor next to a nitro group and a dicyano group in nonlinear optics.

Organic EL materials based on styryl and amine derivatives

Excellent organic electroluminescent materials are needed in order to obtain color EL devices with high performance. We have succeeded in realizing bright and efficient devices with long lifetime in various color regions, based on styryl and amine derivatives.

Tn ← T1 absorption spectra of urethane substituted polydiacetylene in solutions at several pH values

Abstract The first known T n ← T 1 absorption spectra of a potassium salt of poly[4,6-decadiyn-1,10-diol-bis(car☐yl-methyl-urethane)] at three different pH values (7.5, 7.1, and 6.0) were measured over a wavelength region of 400–900 nm by use of a Q -switched Nd: YAG laser. The T n ← T 1 spectra and their lifetimes were found to be relatively insensitive to pH .

Resonant Third-Order Nonlinear Optical Properties of Hemicyanine Doped PMMA Thin Film

Abstract The resonant third-order nonlinear optical properties of hemicyanine, 3-methyl-2-(6-morpholino-1,3,5-hexatrienyl)-benzoxazolium iodide (HC) doped polymethylmethacrylate (PMMA) thin films were measured by degenerate four- wave mixing (DFWM) at 580nm with 4ps pulses. It was found that the temporal profile of DFWM signal in 0.01M HC doped PMMA film was much different from that in dilute dimethylsulfoxide solution of HC. The decay of DFWM signal in the thin film consisted of the faster component (∼10ps) in addition to the slower one (>100ps). The phase conjugate reflectivity was not proportional to the square of pump intensity and saturated even in the weak pump intensity. The effective X (3) xxxx value of the thin film was relatively large (2.8∼10−9esu) at weak pump intensity (0.03μJ/pulse).