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Reunión de Usuarios y Desarrolladores de Métodos de Simulación de Aragón

Electron Dynamics on Surfaces and Nanostructures

Prof. Cristina Diaz, Madrid
Prof. Sergio Diaz Tendero, Madrid
Prof. Fernando Martin, Madrid

DATE OF EVENT : 05/11/2014       DURATION : 3 day(s)

LOCATION : ZCAM Campus Actur C/ Mariano Esquillor s/n Edificio I+D 50018 Zaragoza
URL : http://www.cecam.org/workshop-1009.html


SUMMARY :

In everyday life we regularly come across phenomena related to materials and surface science. Indeed advances on this area have spurred the development of more efficient technologies and many more are expected in the near future. For example, among the new materials developed in recent years, photovoltaic devices deserve particular consideration. Specifically, organic solar cells have been proposed as an efficient alternative [1,2] to the standard silicon-based cells. The development of these devices relies on the latest advances in materials science, which ultimately require in-depth knowledge of the interaction of atoms and molecules deposited on surfaces when they are exposed to the interaction with light: photoinduced charge transfer processes.

An important tool holding significant promise for future applications are surface plasmon polaritons (SPPs), collective light-matter excitations bound to metal surfaces at subwavelength scales. Through their strong concentration of optical fields and precise controllability, SPPs can enable novel approaches for controlling electronic processes on surfaces. For example, it has been shown that they can be used to tune the work function of a metal [8], induce molecular dissociation through electron heating [9], and allow chemical identification of single molecules [10]. Furthermore, SPPs can support ultrafast (few-femtosecond) dynamics due to their potentially large energy bandwidth. This could enable control of surface processes on both nanometer spatial scales and femtosecond temporal scales.

Fundamental electronic processes such as electron capture, electron transfer and electron excitation mechanisms, taking place on surfaces and nanostructures, have an intrinsic importance in different fields of chemistry and physics. For instance, in the near future, miniaturization of electronic devices will bring us to the atomic limit, with single molecules being the key building blocks. In this context, a new multidisciplinary field of research known as molecular electronics has emerged in the last decade (see e.g. [3,4]). The analysis of electron transport through junctions between molecules or between one molecule and one surface is also a crucial point [5,6]. The transient formation of excited electronic states in surfaces constitutes another example (see e.g. [7]). These states play a role in a diversity of phenomena in molecular electronics as well as in chemical reactions at surfaces.
One fundamental challenge to be faced by surface and materials scientists, working in theoretical modelling of atoms and molecules interacting with surfaces and nanostructures, is the development of new theoretical methods for computing the dynamics of electronically excited states, collective electron excitations including plasmons, and electron transport.

[1] C. Brabec et al., in ‘Organic Photovoltaics: Concepts and Realization’, Springer, Berlin, (2003).
[2] A. Goetzberger et al., Mater. Sci. Res., 40, 1 (2003).
[3] P.F. Barbara et al., J. Phys. Chem. 100, 13148 (1996).
[4] A. Nitzan, Ann. Rev. Phys. Chem. 52, 681 (2001).
[5] P. Jelinek et al., Phys. Rev. Lett. 101, 176101 (2008).
[6] H. Park et al., Nature 407, 57 (2000)
[7] Thematic Issue: Photochemistry and Photophysics on Surfaces, Chem Rev. 106, Issue 10 (2006).
[8] J.A. Hutchison et al., Advanced Materials 25, 2481 (2013).
[9] S. Mukherjee et al., Nano Letters 13, 240 (2013).
[10] R. Zhang et al., Nature 498, 82 (2013).