This article reports the photoelectric conversion of 3, 4, 9, lO-perylenetetracarboxylic diimides (PTCDI) in multilayers of Langmuir-Blodgett (L-B) films using the photoelectrochemistry technique and absorption spectroscopy. The rate of electron transfer caused by five different PTCDI molecules was determined and the results demonstrate the photoelectric conversion properties of PTCDI molecules in L-B films.

In order to identify potential candidates as sensors for in vivo EPR oximetry, we carried out a systematic study among commercially available carbon black. A total of 43 carbon blacks were tested. Only two carbon blacks presented a stable, reproducible, and sensitivee response to pO2 for more than 2 months. Therefor, these two carbon blacks should be considered as good candidates to be used as oxygen sensor using in vivo EPR spectroscopy

Head-to-tail molecular arrangements of J-aggregates modify not only the excited state, but also the ground state of the dye chromophore therein. To clarify such modification of the ground state, which is related with the aggregation mechanism, infrared absorption spectroscopy has been applied to J-aggregates of two alkylated merocyanine dyes, 6MeDS and DO, formed in their pure or mutually mixed Langmuir-Blodgett films. Some vibrational modes have been found to be softened upon the J-aggregation. The nature of these vibrational modes has been determined by density functional calculations. Then, it has been concluded that the J-aggregation induces an enhancement of intramolecular charge transfer both in the 6MeDS and DO cases, although these two dyes are largely different in their tendency to form J-aggregates.

UV-visible absorption spectrum of pure 2-methyl-5-octadecyl-N,N'-dicyanoquinonediimine (C18MeDCNQI) Langmuir films and that of C18MeDCNQI-CuI mixed Langmuir films indicated the occurrence of charge-transfer(CT) reactions at the air-water interface in the latter case. These Langmuir films were deposited onto solid substrates as Langmuir-Blodgett(LB) films by the horizontal lifting method. Polarized UV-visible-IR absorption spectra and x-ray diffraction patterns recorded for the obtained LB films revealed a drastic structural change induced by the CT reactions: An interdigitated bilayer structure was suggested for the pure films, while a monolayer structure for the CT films. Furthermore, the CT degree of the major component of the mixed LB films was estimated at-1, unlike in the case of Cu-DCNQI crystals, for which the CT degree is-2/3.

Langmuir-Blodgett films of mixtures of fatty acids (FA) and a merocyanine dye (DS), bearing one long alkyl chain and one carboxylic group, were prepared at a nitrogen-pure water interface. The films exhibit a distinct and highly anisotropic J-band near 605 nm, even though they do not contain any metallic or ammonium cations. Although an isotropic band was seen in the region of 500-550 nm, the contribution of the J-aggregates was extracted from the observed visible and IR absorption spectra by using the difference in the polarization of the bands. This analysis indicates a change in the electronic structure of DS in the J-aggregates, probably corresponding to intramolecular charge transfer. Furthermore, this analysis also suggests that in this metalfree case, the formation of the J-aggregates is strongly affected by the hydrogen bonding between the carboxylic groups in two DS and that between the carboxylic groups in DS and FA.