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Monte Carlo simulation of exciton bimolecular annihilation dynamics in supramolecular semiconductor architectures

Daniel, Clement and Westenhoff, Sebastian and Makereel, Francois and Friend, Richard H. and Beljonne, David and Herz, Laura M. and Silva, Carlos (2007) Monte Carlo simulation of exciton bimolecular annihilation dynamics in supramolecular semiconductor architectures. JOURNAL OF PHYSICAL CHEMISTRY C, 111 (51). pp. 19111-19119.

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Abstract

We present a simulation of exciton dynamics in supramolecular assemblies of an oligo-p-phenylenevinylene derivative monofunctionalised with a quadruple hydrogen-bonding group (MOPV). MOPV molecules form helical stacks in dodecane solution through solvophobic and pi-pi interactions with thermotropic reversibility. We apply a model of incoherent excitation hopping using a Monte Carlo scheme to extract microscopic physical quantities relevant to energy diffusion and bimolecular annihilation processes within isolated nanostructures. We compare the simulation to ultrafast spectroscopic data, namely photoinduced absorption transients at various excitation fluences, their polarization anisotropy, and the dynamic photoluminescence red-shift. We observe that energy diffusion and bimolecular annihilation processes can be described with the same microscopic model based on a Forster-like model that takes into account the spatial extent of the excited state; these two processes are interconnected via the same underlying physics. We extract a high diffusion coefficient (similar to 0.08 cm(2) s(-1)) over the first few picoseconds following excitation, which plays an important role in dictating the bimolecular annihilation dynamics.

Item Type:Article
Subjects:Analytical Science > Metrology and standards in nanotechnology
Analytical Science > Beam methods
Physical Science > Photonics
ID Code:511
Deposited By:INVALID USER
Deposited On:05 Dec 2008 16:35
Last Modified:14 Aug 2009 12:28

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