A small molecule is a low molecular weight organic compound which is by definition not a polymer. Therefore, physical
vapor deposition by evaporation as common for inorganic oxides is often possible. Organic layers can be useful as
components of interference stacks for different functions. A number of organic compounds have interesting UV
absorption characteristics and can be used to protect UV-sensitive polymers such as polycarbonate. In addition, organic
layers can be applied to generate nanostructured thin films with a very low effective refractive index, as shown recently
for polymers. A structured organic single layer can be applied as an antireflective (AR) coating for a glass lens. The
applicability of several small molecule compounds will be discussed in this paper.