The electronic device with a layer of mesoporous silica can be obtained by applying a composition comprising alkoxysilane, a surfactant and a solvent onto a substrate, and by subsequently removing the surfactant and the solvent. The customary dehydroxylation treatment is not necessary if the composition contains a mixture of tetra-alkoxysilane, particularly teatraethoxyorthosilicate (TEOS), and an alkyl-substituted alkoxysilane, particularly a phenyl-substituted, methyl-substituted or ethyl-substituted trialkoxysilane. If both silanes are present in a molar ratio of approximately 1:1, a layer with a dielectric constant of 2.5 or less is obtained.