Regensburg 2010 – scientific programme

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O: Fachverband Oberflächenphysik

O 40: [CPP] Organic Electronics and Photovoltaics II (Joint Session DS/CPP/HL/O)

O 40.6: Talk

Tuesday, March 23, 2010, 15:00–15:15, H37

Influence of system size on simulated charge mobility in amorphous films of tris(8-hydroxyquinolinato)aluminium (Alq3) — •Alexander Lukyanov and Denis Andrienko — Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany

We present the results of a modeling study of the charge transport in amorphous films of tris(8-hydroxyquinolinato)aluminium (Alq3). In our multiscale approach we combine molecular dynamics to generate material morphologies, Marcus theory to evaluate charge hopping rates and kinetic Monte Carlo to simulate charge dynamics. Energetic disorder is taken into account by assigning partial charges to the hopping sites, obtained from DFT B3LYP, 6-311g(d) calculations. In contrast to the previous studies Poole-Frenkel behavior of the mobility is reproduced. Our results indicate strong finite-size effects, meaning that the absolute value of the calculated mobility decreases with the increase of the simulation box size. Simple analogy with a classical percolation problem suggests that very large systems are required to obtain a reliable estimate of the charge carrier mobility.