Titanium dioxide was encapsulated in polymethyl methacrylate and polystyrene by the emulsion polymerization process, and the influence of various polymerization conditions such as the monomer and initiator concentrations and amounts of titanium oxide on the polymerization behavior was investigated. In the polymerization mixture where the end of the polymer chain and the metal oxide surface are oppositely charged, unextractable polymer is formed well. The encapsulating polymers show special structures with high molecular weight and high density. ZUSAMMENFASSUNGTitandioxid wurde durch Emulsionspolymerisation mit Polymethylmethacrylat und Polystyrol verkapselt. Der EinfluD der Monomer-, Initiator-und Ti0,-Konzentration und des pH-Wertes der Emulsion wurde untersucht. In den Emulsionen, in denen die Kettenenden und die MetalloxidoberflBche entgegengesetzt geladen sind, bildet sich nichtextrahierbares Polymeres. Die Kapselpolymeren haben ein hohes Molekulargewicht und eine hohe Dichte, was auf spezielle Strukturen der Polymeren hinweist. 0 1991 Hiithig & Wepf Verlag, Basel CCC 0003-3146/91/$03.00

Zinc oxide encapsulated in various polymers was studied concerning its effect on photoconductivity. Consequently, zinc oxide encapsulated in polystyrene (C‐St‐ZnO) showed a marked light sensitization effect. Further, the tendency was observed that the light sensitization effect was increased in proportion to an increase of the encapsulation ratio. Furthermore, in the composite films of C‐St‐ZnO and polystyrene, the film in which 5% of polystyrene is blended showed a remarkable light sensitization effect. Some studies were carried out with respect to the light sensitization mechanism of this encapsulated zinc oxide by examining the dark current property and the initial rising rate of the sensitized photocurrent.

Poly [p-(methylphenylsilanylene)anthrylene] (PMPSA) which introduced anthracene into the Si-Si backbone structure of poly(methylphenylsilanylene) (PMPS) was synthesized. Schottky barrier photovoltaic cells consisting of semitransparent aluminum and phthalocyanine (H 2 Pc) dispersed in PMPSA were fabricated (H 2 Pc-PMPSA). The effects of a binder polymer and annealing of PMPSA on the photovoltaic characteristics were investigated. Since the conductivity of H 2 Pc-PMPSA composite films increases by the introduction of anthracene and the annealing, the photovoltaic property of H 2 Pc-PMPSA improves markedly. It is found that the power conversion efficiency becomes a maximum for H 2 Pc-PMPSA with a copolymerization ratio (1 : 1) at the annealing temperature of 160 • C for 2 h. The photovoltaic parameters have the following values: the power conversion efficiency η is 4.42%, the fill factor F.F. is 0.30, the open circuit voltage V oc is 0.84 V and the short circuit photocurrent J sc is 0.71 µA/cm 2 . Furthermore, the carrier transport mechanisms of H 2 Pc-PMPSA composite films are discussed.

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