Polymerization of Butylmethacrylate in Isopropanol,Photoinduced by Quantum-Sized CdS Particles

We have established that polymerization of butylmethacrylate photoinduced by cadmium sulfide nanoparticles in isopropanol solutions is of the free-radical type. We give an interpretation of the characteristic features we see in the polymerization kinetics. We have observed and explained quantum-size effects that appear in the dependence of the efficiency of the process on the photocatalyst particle size.     

Temperature-Dependent Photoluminescence of Silver-Indium-Sulfide Nanocrystals in Aqueous Colloidal Solutions

The temperature dependence of the photoluminescence (PL) intensity of colloidal semiconductor nanocrystals (NCs) makes them an appealing option in bio-sensing applications. Here, we probed the temperature-dependent PL behavior of aqueous glutathione (GSH)-capped Ag−In−S (AIS) NCs and their core/shell AIS/ZnS heterostructures. We show that both core and core-shell materials reveal strong PL quenching upon heating from 10 to 80 °C, which is completely reversible upon cooling. The PL quenching is assigned to the thermally activated dissociation of complexes formed by ligands with the metal cations on the NC surface and the introduction of water into the NC coordination sphere. This unique mechanism of the thermal PL quenching results in a much higher temperature sensitivity of the aqueous colloidal AIS (AIS/ZnS) NCs as compared with previously reported analogs capped by covalently bound ligands. Our results are expected to stimulate further studies on aqueous ternary NCs as colloidal luminescent nano-thermometers applicable for ratiometric temperature sensing.     

The effect of PbS nanoparticles on the formation of PbSe in aqueous solutions of sodium selenosulfate and lead(II)

It was established that PbS nanoparticles significantly increase the rate of formation of lead selenide during the reaction of Pb(NO₃)₂ and Na₂SeSO₃ in aqueous solutions of polymers. It was shown that the reaction product consists of PbS/PbSe nanoparticles with a “PbS core-PbSe shell” structure. A correlation was found between the forbidden band widths of the PbS nanoparticles and the PbS/PbSe nanostructures formed during the reaction. __________ Translated from Teoreticheskaya i éksperimental’naya Khimiya, Vol. 42, No. 6, pp. 339–344, November–December, 2006.     

CdS Nanoparticle Photocatalysis of the Chain Oxidation of Sulfite Ions by Molecular Oxygen

High photocatalytic activity was found for colloidal cadmium sulfide nanoparticles in the radical chain oxidation of sulfite ions by molecular oxygen in aqueous solution. The kinetics of this reaction was studied and a mechanism was proposed, which is in satisfactory accord with the experimental data.     

Photopolymerization of Butyl Methacrylate in the Presence of Nanoparticles of ZnO,Sensitized to Visible Light with Xanthene Dyes

The photopolymerization of butyl methacrylate in isopropanol with participation of nanoparticles of wide-gap semiconductor ZnO has been studied. The possibility of sensitizing ZnO nanoparticles to visible light with a series of halogenated fluoresceins has been established. The rate of photoinitiation of polymerization in the systems studied is principally determined by the rate of electron transfer from the photoexcited molecule of the sensitizer into the conduction zone of the semiconductor nanoparticles.     

Photopolymerization of Butyl Methacrylate Initiated by Hydrated Ferric Oxide Nanoparticles

Colloidal hydrated ferric oxide nanoparticles in 2-propanol solution are efficient initiators of the polymerization of butyl methacrylate by the action of UV and visible light. The kinetics of this reaction was established and elucidated. A mechanism of the photoinitiated polymerization involving photoexcited semiconductor particles was proposed in accord with the experimental and literature data.     

Preparation of colloidal CdSe and CdS/CdSe nanoparticles from sodium selenosulfate in aqueous polymers solutions

Cadmium selenide nanoparticles formation at the interaction between CdCl2 and Na2SeSO3 in aqueous solutions of sodium polyphosphate and gelatin has been studied. Structural and optical properties of CdSe nanoparticles have been characterized. It has been shown that the temperature and the ratio of reagents concentrations are the basic parameters, controlling the size of CdSe nanoparticles. Photocatalytic activity of CdS nanoparticles in Na2SeSO3 reduction has been found and investigated; structural and optical properties of binary CdS/CdSe nanoparticles have been characterized. This photoreaction, when carried out in the presence of CdCl2, results in the formation of composite CdS/CdSe nanoparticles. It has been shown that slow interaction of adsorbed selenosulfate with surface-trapped CdS conduction band electrons is the limiting stage of the photocatalytic reaction.     

Photochemical reduction of sulfur in the presence of ZnO nanoparticles in ethanol

The photochemical reduction of sulfur by the action of ZnO nanoparticles of various shapes and sizes under the conditions of stationary and pulsed photoexcitation was studied. The mechanism of this process was proved; the main route to the formation of the reaction product zinc sulfide is reduction of the sulfur by photochemically produced metallic zinc. It was demonstrated that ordered agglomerates of ZnS nanoparticles in the form of nanotubes and nanorods are formed in the systems based on ZnO nanorods.