title: Moderate doping leads to high performance of semiconductor/insulator polymer blend transistors.
abstract: Polymer transistors are being intensively developed for next-generation flexible electronics. Blends comprising a small amount of semiconducting polymer mixed into an insulating polymer matrix have simultaneously shown superior performance and environmental stability in organic field-effect transistors compared with the neat semiconductor. Here we show that such blends actually perform very poorly in the undoped state, and that mobility and on/off ratio are improved dramatically upon moderate doping. Structural investigations show that these blend layers feature nanometre-scale semiconductor domains and a vertical composition gradient. This particular morphology enables a quasi three-dimensional spatial distribution of semiconductor pathways within the insulating matrix, in which charge accumulation and depletion via a gate bias is substantially different from neat semiconductor, and where high on-current and low off-current are simultaneously realized in the stable doped state. Adding only 5 wt% of a semiconducting polymer to a polystyrene matrix, we realized an environmentally stable inverter with gain up to 60.
authors.affiliation: Institut für Physik und Astronomie, Universität Potsdam, Karl-Liebknecht-Strasse 24-25, 14476 Potsdam, Germany.
authors.forename: Guanghao
authors.initials: G
authors.lastname: Lu
authors.forename: James
authors.initials: J
authors.lastname: Blakesley
authors.forename: Scott
authors.initials: S
authors.lastname: Himmelberger
authors.forename: Patrick
authors.initials: P
authors.lastname: Pingel
authors.forename: Johannes
authors.initials: J
authors.lastname: Frisch
authors.forename: Ingo
authors.initials: I
authors.lastname: Lieberwirth
authors.forename: Ingo
authors.initials: I
authors.lastname: Salzmann
authors.forename: Martin
authors.initials: M
authors.lastname: Oehzelt
authors.forename: Riccardo
authors.initials: R
authors.lastname: Di Pietro
authors.forename: Alberto
authors.initials: A
authors.lastname: Salleo
authors.forename: Norbert
authors.initials: N
authors.lastname: Koch
authors.forename: Dieter
authors.initials: D
authors.lastname: Neher