From molecular design to plastic electronics: A multi-scale modeling perspective
Karin Zojer
Institut für Festkörperphysik
http://www.if.tugraz.at
10:20 - 10:40 Thursday 23 October 2014 Rechbauerstrasse 12, HSII In this talk, an introduction to the scope and challenges related to multi-scale modelling of organic electronic devices is given.
Organic electronic devices hold the promise to combine semiconducting properties with the mechanical properties of plastic and with an unprecedented level of flexiblity in creating potential functionalities by chemical design. The properties of organic semiconductors are largly determined by the chemical structure and packing of the molecules or polymer chains. The deposition such substances into a sequence of ultra-thin layers (50-200 nanometers in total) is sufficient to realize (opto-) electronic applications, such as organic light emitting diodes, thin film transistors, or solar cells. Moreover, the ease of fabrication on subrates such as Si-wafers, glass, or even plastic foils permit device extensions up to centimeters, i.e., the realization of large area applications.
From a theoretical point of view, such vastly different device dimensions pose the challenge to consecutively model mechanisms and processes occuring at length scales ranging from nanometers to centimeters to reliably predict the functionality of such a device under operating conditions.
To illustrate the state of the art in the field of multi-scale device simulations, selected individual modeling tasks will be shown and their role in the entire modeling chain highlighted. These may start, e.g., the prediction of (i) the geometry of a single molecule, (ii) the molecular packing in the layer, and proceed to (iii) the assessment of charge "hopping" rates from one molecule to another, and (iv) the prediction of the overall device current for a given point of operation.
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