Tailor made mie scattering color filters made by size-tunable titanium dioxide particles

Particles with sizes ranging from nanoscale to microscale were synthesized by the reaction of titanium isopropoxide (TTIP) with acetic, butyric, valeric, or octanoic acids. When acetic acid was used, anatase nanoparticles with diameters of approximately 15 nm were obtained while the other carboxylic acids yielded amorphous submicron-sized spheres. Moreover it is possible to adjust the particle size of the powders since it is proportional to the length of the alkyl group on the carboxylic acids used. When submicron-sized particles were coated on a transparent substrate (quartz or glass), different wavelengths of light were scattered. Thus color filters with specific wavelengths could easily be made by coating powders synthesized from specific carboxylic acids on the transparent substrate.