Formation and Deposition of Stable Silver Nanoparticles Encapsulated in Solid Spheres

We prepared solid spheres, with diameters between 100 and 400 nm, encapsulating silver nanocrystallites (about 20 ± 10 nm in diameter), by heating colloidal solutions of silver in methoxyethanol at 120 °C. Stable coatings were obtained using spin coating and rapid thermal processing on optical glass substrates. UV-Vis spectroscopy measurements demonstrated the remarkable stability against aggregation and particle growth, even after prolonged heating at 120 °C and exposed at direct sunlight, of the solutions, even using high concentrations of silver (1 M), and coatings of spheres encapsulating silver.