Nanoparticles of antimony-doped tin oxide (ATO) were characterized for 0–33.3% Sb doping, both in aqueous dispersion and as dried powder. Antimony is incorporated in the cassiterite SnO2 structure of the ATO nanoparticles (d ≈ 7 nm) up to the highest doping levels, mainly as SbV, but with increasing Sb doping the SbIII content increases. We found adsorption of NH3 at the particle surface and evidence for the incorporation of nitrogen in the crystal lattice of the particles. The total nitrogen content increases with increasing Sb doping of the particles. Compact powder conductivity measurements show an increase in conductivity of ATO powder up to 13% Sb and a small decrease for higher Sb contents. Furthermore, we show that these particles can be used to prepare highly transparent conductive cross-linked ATO/acrylate nanocomposites with a continuous fractal particle network through the polymer matrix and a very low percolation threshold (ϕc ≈ 0.3 vol%).

In the absence of another (photo)radical initiator Sb:SnO2nanoparticles (0≤Sb≤13at %) photocatalyze during irradiation with UV light the radical polymerization of (meth)acrylate monomers. When cured hard and transparent (>98%) films with a low haze (<1%) are required, when these particles are grafted in advance with 3-methacryloxypropyltrimethoxysilane (MPS) and doped with Sb. Public knowledge about the photocatalytic properties of Sb:SnO2nanoparticles is hardly available. Therefore, the influence of particle concentration, surface groups, and Sb doping on the rate of C=C (meth)acrylate bond polymerization was determined with aid of real-time FT-IR spectroscopy. By using a wavelength of irradiation with a narrow bandgab (315±5 nm) the influence of these factors on the quantum yield (Φ) and on polymer and particle network structure formation was determined. It is shown that Sb doping and MPS grafting of the particles lowers Φ. MPS grafting of the particles also influences the structure of the polymer network formed. Without Sb doping of these particles unwanted, photocatalytic side reactions occur. It is also shown that cured MPS-Sb:SnO2/(meth)acrylate nanocomposites have photoconduction properties even when the particle concentration is as low as 1 vol.%. The results suggest that the Sb:SnO2(Sb>0at %) nanoparticles can be attractive fillers for other photocatalytic applications photorefractive materials, optoelectronic devices and sensors.

For the first time it is shown that N-doped SnO 2 nanoparticles photocatalyze directly the polymerization of the C=C bonds of (meth)acrylates under visible light illumination. These radical polymerizations also occur when these particles are doped with Sb and when the surfaces of these particles are grafted with methacrylate (MPS) groups. During irradiation with visible or UV light the position and/or intensity of the plasmon band absorption of these nanoparticles are always changed, suggesting that the polymerization starts by the transfer of an electron from the conduction band of the particle to the (meth)acrylate C=C bond. By using illumination wavelengths with a very narrow band width we determined the influence of the incident wavelength of light, the Sb-and N-doping, and the methacrylate (MPS) surface grafting on the quantum efficiencies for the initiating radical formation (Φ) and on the polymer and particle network formation. The results are explained by describing the effects of Sb-doping, Ndoping, and/or methacrylate surface grafting on the band gaps, energy level distributions, and surface group reactivities of these nanoparticles. N-doped (MPS grafted) SnO 2 (Sb ≥ 0%) nanoparticles are new attractive photocatalysts under visible as well as UV illumination.

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