FWF-TRP239-In-situ characterisation - In-situ production, electrical and surface analytical characterization of novel organic thin film transistors

Electronic devices based on organic materials are generally expected to be of great future importance. Some of the advantages of this type of plastic electronics are their flexibility, cheap large area production and lightweight. Even the production of green, disposable electronics is envisioned. Nevertheless, there are still great challenges, which have to be overcome to bring this technology to the market. The challenges are the reproducibility, stability and electron mobility, to mention just a few. In the proposed project we claim to make considerable progress in the fabrication, characterization and optimization of novel organic model devices. To reach this goal the collaboration of two research institutes, the Institute of Solid State Physics at the Graz University of Technology and the Institute of Surface Technologies and Photonics at the Joanneum Research Forschungsgesellschaft in Weiz is suggested. In both institutes a long-time expertise on the fabrication and characterization of organic films and organic electronic devices exists. In this project the applicants will produce and investigate novel organic model thin film transistors (OTFT). The novelty of this project is the unique combination of surface science methods for the film characterization with in-situ studies of the electrical properties of OTFTs during film preparation. It is known that the morphology, structure and chemical composition of the very first layers mainly determine the functionality of an organic transistor. The organic layers, as well as the contact electrodes, will be prepared by physical vapor deposition and the films will be characterized by a variety of surface analytical techniques: Auger electron spectroscopy (AES), X-ray photoelectron spectroscopy (XPS), thermal desorption spectroscopy (TDS), work function measurements (), atomic force microscopy (AFM), etc. In this project we will explore promising novel materials; both for the active layer (e.g. PTCDI, rubrene, phthalocyanine) as well as for the dielectric layer (e.g. PVP, PVCi, BCB, PMS). The main issue will be the optimization of the charge carrier transport as a function of the thickness, morphology and structure of the semiconductor layer and electrode layer in top and bottom contact geometry. Although the main focus of this project is put on organic thin film transistors, the gained findings will be also of relevance for the production of other organic electronic devices, e.g. solar cells, light emitting diodes and sensors. Areas of application will be the energy and entertainment industry, but applications in medicine, for green technology and food processing industry can also be anticipated.