Specifics of the formation of regular opal structures from spherical silica particles in various colloidal solutions

Photonic crystal opal matrices are bulk spatial periodic structures based on amorphous spherical silica particles whose size is compatible with the wavelengths of the visible light spectrum. These structures are very promising and can be used as matrices for new functional materials. The article studies the formation of a regular opal structure on dielectric substrates by means of the evaporation of droplets and layers of colloidal solutions based on water and ethanol with various oncentrations of spherical SiO2 particles with a diameter of about 250 nm synthesised using the Stöber method.