Abstract: Semiconductor nanoparticles of CdS and ZnS have been synthesized in AOT-isooctane reverse micelles. It was found that the fluorescence quantum efficiency of the semiconductor particle decreases with increasing water content. This is attributed to the dilution of Cd²⁺ or Zn²⁺ ions at the interface of semiconductor particles. These cations favor the formation of sulfur vacancy, where the radiation recombination of the electron-hole pair occurs. The fluorescences of CdS and ZnS particles are effectively quenched by the addition of Ag⁺ ions.Such a process can be described by the Poisson statistics for the distribution of AG+ ions in reverse micelles. An efficient microheterogeneous electron-transfer was observed from pyrene to the CdS particles formed in AOT-isooctane reverse micelles,whereas no electrontransfer can be observed at ZnS particles. This is explained with considering the relative positions of the conduction bands of CdS and ZnS particles with respect to the oxidation potential of the excited singlet of pyrene. Adsorption of Cu²⁺ and Ag⁺ ions on the ZnS particle leads to the formation of mixed semiconductor particles, Cu_x-Zn_1-xS and Ag_2xZn_1-xS, the conduction bands of which are adjusted between those of ZnS and CuS or Ag₂S. Electrons can be injected from pyrene to these mixed particles. The efficiency of the electron-transfer is determined by the probability of the contact of pyrene with the semiconductor particles.

Key words: semiconductor nanoparticle, reverse micelles, electron transfer, pyrene