Microspheres were fabricated from phthalimide-substituted porphyrin derivatives. Microscopic analysis showed that the structures of the supramolecular assemblies synthesized in the present study were spherical, with diameters in the sub-micrometer to micrometer range. The size of the microspheres could be controlled by changing the concentration of the casting solution. The spectroscopic properties of the microspheres were measured to determine the influence of their structural components. Thermal studies indicated that the temperature at which these structures became unstable was lower than the bulk melting point. During I-V measurements on devices composed of these microspheres, it was found that the current increased upon light irradiation, and the characteristic photoresponse properties of these devices were reproducible.
Department of Electrical Engineering and Computer Science, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603, Japan. hiro.ozawa@mail.cstm.kyushu-u.ac.jp