Graphene Field-Effect Transistor as a High-Throughput Platform to Probe Charge Separation at Donor-Acceptor Interfaces.

In organic and low-dimensional materials, electrons and holes are bound together to form excitons. Effective exciton dissociation at interfaces is essential for applications such as photovoltaics and photosensing. Here, we present an interface-sensitive, time-resolved method that utilizes graphene field effect transistor as an electric-field sensor to measure the charge separation dynamics and yield at donor-acceptor interfaces. Compared to other interface-sensitive spectroscopy techniques, our method has a much reduced measurement time and can be easily adapted to different material interfaces. Hence, it can be used as a high throughput screening tool to evaluate the charge separation efficiency in a large number of systems. By using zinc phthalocyanine/fullerene interface, we demonstrate how this method can be used to quantify the charge separation dynamics and yield at a typical organic donor-acceptor interface.