Band-Gap Engineering of Zinc Oxide Colloids via Lattice Substitution with Sulfur Leading to Materials with Advanced Properties for Optical Applications Like Full Inorganic UV Protection

The advanced application of wide-band gap semiconductors in areas like photovoltaics, optoelectronics, or photocatalysis requires a precise control over electronic properties. Zinc oxide is favorable for large-scale technological applications now and in the future because of the large, natural abundance of the involved, chemical elements. Often it is important that the band gap can be controlled precisely. While a blue-shift of the band gap can be reached quite easily using the quantum-size effect, it is still very difficult to achieve a red-shift. We present a powerful method for the band gap engineering of ZnO via the incorporation of sulfur as a solid solutions. The reduction of the energy gap is controlled by ZnO 1– x S x composition, whereas the latter is adjusted via special organometallic precursor molecules. The material can be supplied in a continuous fashion and in a more refined morphology, for instance spherical ZnO 1– x S x colloids with sizes below λ vis /2 (≈ 200 nm). As a concrete application of contemporary importance first steps toward the full inorganic UV protection are made.