Structural and optical properties of langmuir-blodgett films of the electron acceptor 2-octadecylthio-1,4-benzoquinone

The electron acceptor 2-octadecylthio-1,4-benzoquinone forms stable monolayers at air/water interfaces. Transfer to hydrophobic substrates yields Y-type Langmuir-Blodgett films. By studies of multilayers using X-ray diffraction and spectroscopy with polarized light a structure model is obtained which shows that a simultaneously close packing of the head group and alkyl chains is possible. The oxygen-carbon bonds in the quinone head group are oriented along the substrate normal according to the structure model.