Growth of Silver Nanoclusters on Mono layer Nanoparticulate Titanium-oxo-alkoxy Coatings

We report on a new method of preparation of Ag-N-TiO2 nanoparticulate coatings with stable and highly reproducible morphology. The silver nanoparticles are grown on monolayer titanium-oxo-alkoxy nanoparticulate coatings by silver ions reduction at UV-A light illumination. Their size and surface number density increase with the irradiation time. The AFM and high-resolution SEM and TEM measurements of height (h) and lateral size (D) of the silver nanoparticles show that their shape approaches spherical segment with h/D = 1/4 at long irradiation times. The size correspondent to the maximum of the particles size distribution curve tends to D = 12 nm with half width at full-maximum Delta D = 4 nm. The evaluation of the deposited silver mass results in the quantum yield of the deposition process close to 100% at the process beginning and the atomic surface density of N-Ag = 1 25 x 10(7) at/mu m(2) at the process saturation. The absorption spectra of the surface plasmon shift from 425 to 525 nm. The spectra are successfully modeled assuming small dispersion of the oblate particle shape asymmetry Delta(h/D) approximate to 0.25 and surface number density below 2500 part/mu m(2). Mutual interaction between the silver particles is shown to weakly affect the spectra. Two-photon photoluminescence images of the composite nanocoatings show the characteristic hot-spot pattern of surface plasmons.