Sol-gels 59 Sol-gel process 38 Sols 26 Thin films 24 Titanium dioxide 18 Zinc oxide 16 Nanoparticles 14 Silica 12 Sol-gel spin coating 12 Thermoelectric equipment 11 Coatings 10 Electronic equipment 10 Substrates 10 Energy gap 9 Field emission microscopes 9 Field emission scanning electron microscopy 9 Optical properties 8 Scanning electron microscopy 8 Titanium oxides 8 X ray diffraction 8 Synthesis (chemical) 7 Manufacture 6 Nanostructured materials 6 Oxide films 6 Particle size analysis 6 Silicon 6 Sol-gel spin coating method 6 Sustainable development 6 Annealing 5 Atomic force microscopy 5