Colloidal dispersions as well as bulk materials can be optically investigated via UV-vis-NIR spectroscopy with the help of a Cary5000 spectrophotometer from Agilent. This instrument enables measurements in the wavelength range of 175-3300nm and absorbance values of up to 8 a.u., which allows for highly accurate measurements. Measurements in solution using quartz cuvettes are equally possible as investigations of solid-state thin film samples on microscopic glass slides.