The dissociation of excitons at a donor-acceptor interface in organic photovoltaic devices is an important but poorly
understood process that takes place over multiple length and time scales. Here, we introduce a method to resolve
photoinduced charge movement at an organic heterojunction in both time and space through observation of the Stark
shift induced in a nearby J-aggregate probe layer. Using ultrafast transient absorption measurements, we show that this
technique provides an opportunity to quantify the recombination and separation dynamics of geminate charge pairs over
the entire sub-picosecond to millisecond range of relevant time scales.© (2012) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.