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Comparative study of optical properties of alkylthio-group-substituted phthalocyanine rare-earth metal sandwich complexes (͓(C n S͒ 8 Pc͔ 2 M,MϭEu,Lu,Tb) is presented. Photoluminescence and photoconductivity of ͓(C n S͒ 8 Pc͔ 2 M complex is very weak. Two photoluminescence bands were observed at around 400-650 and 720-800 nm in chloroform solution corresponding to the Soret and Q bands in the absorption spectra, respectively. However, the emission from Eu 3ϩ ion ͑as well as Tb 3ϩ ) was not found compared with other Eu complexes because the 5d levels of the Eu 3ϩ ion lie higher than the triplet level of the ligand. The significant enhancement of the photoconductivity of ͓(C 16 S͒ 8 Pc͔ 2 M after C 60 doping is reported. The photoconductivity is positive at the low electric field in the ohmic regime while it becomes negative at the high electric field upon photoexcitation with strongly absorbed light. The negative photoconductivity is attributed to space-charge effects. The mechanism of photoluminescence and photoconductivity are discussed by taking the electronic energy schemes of phthalocyanine ligands and lanthanide ion and C 60 into consideration.

Novel carboxy-substituted poly(p-phenylene vinylene), poly(1,4-(2-(5-carboxypentyloxy)-5-methoxyphenylene)vinylene) (CPMOPPV) has been synthesized. The obtained polymer is soluble in organic solvents, such as acetone and ethanol, and the sodium salt of CPMOPPV is soluble even in water. The optical properties of CPMOPPV, such as optical absorption and photoluminescence have been studied, and yellow-electroluminescence devices have been fabricated. The electronic energy structure of CPMOPPV has been determined by optical and electrochemical measurements. CPMOPPV has been demonstrated to be one of the candidate polyanions for fabrication of the organic multilayer structure by the self-assembly technique.

Current–voltage characteristic and electroluminescence (EL) have been observed in a heterojunction device using a conducting polymer, poly(2-methoxy-5-dodecyloxy1,4-phenylenevinylene) (MDDO-PPV), and a diamond film prepared by microwave plasma chemical vapor deposition with Al/MDDO-PPV/diamond/Si structure. These results can be interpreted in terms of the hole injection from diamond into MDDO-PPV and occurrence of radiative recombination in MDDO-PPV. The electronic energy structure evaluated from electrochemical and photoelectrochemical measurements suggests that the diamond film is suitable for hole injection in the conducting polymers, being consistent with the current–rectifying characteristics of the EL device. The observed photocurrent spectra suggest the important roles of surface and/or interface effects of the diamond films.