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Titanylphthalocyanine takes various crystal polymorphism. The titanylphthalocyanine with Y-form shows excellent optical and photoelectric conversion. However, preparing the Y-form titanylphthalocya...

Drug nanoparticles of water-insoluble bioactive compounds are potentially applicable in next-generation drug delivery systems (DDSs). As an example of such nanoparticles, the dimeric podophyllotoxi...

Diarylethene nanorods have been fabricated through the reprecipitation method by using cis-1,2-dicyano-1,2-bis(2,4,5-trimethyl-3-thienyl)ethene (CMTE), and their crystal structure and photochromic ...

In the fabrication of polyimide (PI) spherical nanoparticles by the reprecipitation method, intriguing uniquely shaped objects, including doughnut-like and/or hollow, and polymeric soccer ball-shap...

Single molecular chains of π-conjugated polymers such as polythiophene and polydiacetylene were clearly observed by STM, and their molecular structures and/or conformation were discussed in relation to bonding characteristics. It should be noted that even molecular weight could be determined using well-resolved STM images.

Using reprecipitation technique from high temperature and high pressure liquid, C60 microcrystals with size of about 40 nm and narrow size distribution could be fabricated in the dispersion liquid. And it was found that the optical properties of C60 microcrystals were also dependent on crystal size in a similar manner as the other π-conjugated organic microcrystals.

In this study, we found that, in perylene microcrystals, luminescence peak position from free-exciton state was gradually shifted to high energy side with reducing the crystal size, even if the microcrystals were fabricated by different kinds of preparation techniques. The life time of luminescence from self-trapped exciton state became shorter when the crystal size reduced. The main reason was estimated to be based on the change of lattice state.

The second-order hyperpolarizability (β) of pyridinium cations with cutoff (λco) shorter than 400 nm were studied by semiempirical calculation and the hyper-Rayleigh scattering (HRS) technique. The β value of 4-dimethylaminopyridinium (λco=390 nm) was evaluated to be about 1.5 times larger than that of p-nitroaniline (λco=473 nm) in methanolic solution using 1064 nm light as a fundamental beam.