Preparation and characterisation of AG colloids in ceramic matrices by the sol-gel-process

Abstract

A synthesis route for the preparation of Ag colloid containing coatings in SiO2, TiO2, ZrO2 and mixed SiO2/TiO2 matrices and SiO2/ZrO2 matrices of different molar ratios has been developed. As a result different, intensely coloured coatings, depending on the refractive index of the matrix, were obtained. In Ag colloid containing mixed SiO2/TiO2 matrices and SiO2/ZrO2 matrices a significant red shift of the peak position wavelength lambda max of the Ag plasmon resonance band with decreasing content of SiO2 was observed and it was possible to adjust lambda max of the Ag colloids from yellow (pure SiO2 matrix: lambda max=405 nm) to bluish-violet (pure TiO2 matrix: lambda max=535 nm or pure ZrO2 matrix: lambda max = 530 nm) by the refractive index of the matrix. These results are in good agreement with the calculations obtained from Mie theory for Ag colloid radii of approximately 20 nm.