CdS and CdSe nanoparticles were prepared in organic solvents in the presence of poly(N-vinyl-2-pyrrolidone) (PVP). PVP plays an essential role in preventing the flocculation of concentrated nanoparticles (stabilizing effect), and in controlling the particle size under the influence of the solvent used. FT-IR measurements were performed to study the effect of the functional groups of PVP on particle size control at molecular levels. The PVP-coated CdS and CdSe nanoparticles obtained were dispersed in acrylonitrile-styrene (AS) copolymer or poly(2-hydroxyethyl methacrylate) (PHEMA) organic films, and third-order nonlinear optical susceptibilities |χ(3)| of these films were measured using a degenerate four-wave mixing (DFWM) technique. The largest |χ(3)| value of 1.1×10-7 esu was obtained by excitonic resonant excitation for about 4.0 vol% CdS-doped PHEMA film.

A microcomputer-controlled nanosecond diffuse reflectance laser photolysis system was developed and applied to p-terphenyl powder systems. The triplet absorption spectrum of microcrystalline powders is broader and red-shifted compared to the molecular triplet state in solution. Possible contributions of an optical artifact and an impurity were rejected by examining powder systems doped with naphthacene and diluted with NaCl as well as poly(methyl methacrylate). p-Terphenyl adsorbed on silica gel and included in β-cyclodextrin gave different triplet spectra, which are interpreted in terms of conformational structure of p-terphenyl. Decay processes and an oxygen effect are also discussed.

Triplet state and photoinduced charge separation dynamics under adsorption was Confirmed for the first time for the polymer without or with coadsorbed electron acceptor, respectively. The absorption spectrum of the triplet polymer is similar to the Tn← T1 band of N‐ethylcarbazole, showing no appreciable interchromophoric interaction. Absorption spectra of the coadsorbed systems comprise the polymer cation and electron acceptor anion. The ion radicals on the cellulose substrate undergo mutual recombination, and simple uni‐ and bimolecular decay kinetics do not hold. This mechanism was compared with that for poly(N‐vinylcarbazole) film.

CdS quantum-confined ultrafine particles (Q-ufp) were prepared in colloidal solutions in the presence of styrene monomer under photoirradiation. By means of transmission electron microscopy analysis, it has been experimentally verified for the first time that the prepared CdS Q-ufp were coated with polystyrene layer, and the particle size distribution was controlled by selecting the wavelength of the irradiating laser light: shorter wavelength light irradiation gave smaller CdS Q-ufp. A mechanism for particle size control through photocatalytic polymer coating is discussed to explain the experimental results; the particle size distribution or corresponding UV-vis absorption spectra were simulated using the proposed model. As a result, the oxidation potential of styrene monomer, relative to the highest occupied molecular orbital (HOMO) or the top of the valence band of CdS Q-ufp which depends on the particle size, is important for electron transfer necessary for initiating the polymer coating process.