Organic Bidirectional Phototransistors Based on Diketopyrrolopyrrole and Fullerene

摘要

It is shown that simple bilayer devices consisting of the diketopyrrolopyrrole (DPP) monomer Ph-TDPP-Ph as donor and C-60 as acceptor feature J-V-characteristics of a bidirectional organic phototransistor where illumination intensity plays the role of the gate voltage as compared to a conventional field-effect transistor. The output current may therefore be controlled both electrically and optically. The underlying mechanism is based on the good charge transport in Ph-TDPP-Ph and C-60, the intrinsic dissociation properties of C-60, and the presence of an injection barrier for holes. In addition to this, it is demonstrated that the observed behavior of the DPP/C-60 system allows the realization of basic logic elements like NOT-, AND-, and OR-Gates, which may provide the basis for advanced analog and digital applications.