Phosphonic acids (PAs) are useful as surface modifiers to tailor work function and increase surface wettability of transparent conductive oxide electrodes in organic photovoltaic devices.  When ordered PA monolayers are formed on oxide substrates, the interface dipole and electronic structure are affected by the functional group properties, binding mode and orientation  of the PA modifiers. Using octylphosphonic acid (OPA), F13-octylphosphonic acid (F13OPA), perfluorinated phenyl phosphonic acid (F5PPA), benzyl phosphonic acid (BnPA), and perfluorinated benzyl phosphonic acid (F5BnPA) as a group of representative model PA surface modifiers, polarization modulation-infrared reflection adsorption spectroscopy (PM-IRRAS) was used to determine binding mode and molecular orientation on indium-zinc oxide (IZO) substrates. In addition to binding of the PA monolayer, the surface modification process induces the formation of defects on these IZO substrates as indicated by changes in the IR responses of these interfaces. The presence of such defects is important, as they likely change surface electronic properties that affect electron transfer and charge recombination processes at these interfaces in devices.

Orientation and reaction chemistry of phosphonic acid-modified indium-zinc oxide surfaces in organic photovoltaic devices

247th National Meeting (2014)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.