By Prof. Abdelkader Kara, University of Central Florida, USA.
Organic materials are playing an increasing role in electronics and particularly in energy related systems such as photo-voltaic for energy harvesting and light emitting diodes for lighting. A great amount of research has been devoted to this field in the last couple of decades. Due to the complex nature of bonding at the interface between these materials and the contact material, to form a device, an accurate and deep understanding of the characteristics of this interface is lacking. Density Functional Theory (DFT) provided a very strong tool to study a variety of systems, including metal substrates. On the other hand, van der Waals (vdW) approaches model quiet well the characteristics of organic materials. However, when the contact is made between organic materials and metal surfaces, several phenomena enter into play, making the system poorly described by either of those two approaches. Recently, efforts have been spent to introduce self-consistently van der Waals interactions into DFT, which I systematically explored for many molecule/metal systems.
These computational studies use both standard density functional theory (DFT) as well as exploiting the self-consistent inclusion of dispersive (vdW) forces, with the aim of obtaining their effects and dependence on the surface chemical and structural properties. I will present the results on how the interface characteristics between organic materials and metal surfaces change with the characteristics of molecules, the degree of reactivity, as well as the geometry of the surface. The results obtained for the adsorption of acenes, thiols and other molecules with CN groups on several transition metal surfaces (Au, Ag, Cu, Ni, Pd, Pt and Rh) will be presented.
Professor Abdelkader Kara joined the Physics Department at the University of Central Florida, the second largest university in the USA in 2006. He obtained his PhD in 1985 from the University of Lille and CEA Saclay. He worked at several Universities in the USA and England. Prof. Kara is a trained experimentalist and computational scientist. Though his main research is on the computational front, he regularly participates in experimental research.
His research activities include the computational study of 2D materials on metal surfaces. Professor Kara has developed several computational tools that include a Real Space Green’s Function method to calculate the phonons of complex materials. He also developed a new smart Kinetic Monte Carlo method (SL-KMC) that uses artificial intelligence. Several researchers have followed his foot-steps in developing a new paradigm for KMC.
He is currently exploring the van der Waals effects in organic materials/metal surfaces interactions.
He is one of the pioneers in the field of Silicene, the silicon counterpart of graphene.
Professor Kara received several awards for teaching and research and he is a recipient of the Scroll & Quill Award for Excellence in Research.
Professor Kara published over 150 well cited papers and reviews in high impact journals. He also organizes international meetings, workshops and summer schools in Morocco, France, USA and China.