Ambipolar field-effect transistor based on α,ω-dihexylquaterthiophene and α,ω-diperfluoroquaterthiophene vertical heterojunction

Abstract

Organic field-effect transistors (OFETs) are alternative emerging device structures for efficient light generation, that could provide a novel architecture to address open issues like exciton-contact and exciton-charge quenching, that still limit the OLEDs efficiency and brightness. Recently, it has been introduced by our research group the model of a tri-layer organic heterostructure implemented in a field-effect configuration, that allows preventing at one time the exciton-metal as well as the exciton-charge quenching in an organic electroluminescence generating device. The device active region is formed by a central optical layer sandwiched between an electron and a hole field-effect conducting film. In order to understand the complex phenomena that happens at the interfaces, with the target to fabricate the most balanced ambipolar structure with high morphological compatibility and high mobility in a vertical heterojunction geometry, we made a preliminary study of a single layer and bi-layer OFET structure composed by α,ω-dihexylquaterthiophene (DH4T) and α,ω-diperfluoroquaterthiophene (DHF4T). By means of this study we showed a new highly balanced ambipolar OFET made of these materials, a first step toward their implementation in a more complex structure as the tri-layer is.