Photoinduced processes in functionalized and organized organic semiconductors

Energy and electron transfer constitute the most pivotal photoinduced processes in photosynthesis and in opto-electronic devices such as organic solar cells and optical sensors.  Controlling the flow of energy and electrons in molecules and materials thus is of fundamental importance to maintain a sustainable society. In creating cheap photonic applications, organic materials such as conducting polymers and organic dyes play a major role.

With various spectroscopic techniques available in the Molecular Photonics group, we are able to probe the properties that control these photoinduced processes in molecules, supra-molecular systems and nano-materials. Especially femtosecond transient absorption (FTA) spectroscopy in combination with global and target analysis (in collaboration with Ivo van Stokkum at the VU) is our most important tool. Nanosecond transient absorption, time resolved emission and steady state spectroscopic techniques are also applied.

In close collaboration with various expert groups in the world ( Eindhoven, Groningen, Würzburg, Angers) we develop chromophoric photofunctional assemblies in solution or in thin films. Recent work has shown that we can probe organizational effects created upon annealing of 20 nm thin films of an organic dye with FTA.

Highlights include C60-capped low-bandgap oligomers; fullerene–perylene-(bis)dicarboximide (C60-PDI) conjugates; calixarene linked multichromophoric PDI systems for energy and electron transport in which we probe ground-state conformations with excited-state dynamics of charge separation and recombination; development of a Karplus relation for Charge Transfer for e.g. foldamer linked donor-acceptor systems.

Contact: René Williams, e-mail: R.M.Williams@uva.nl
Molecular Photonics (UvA)
http://home.uva.nl/r.m.williams/

 

Williams1  williams4
Photochem. Photobiol. Sci., 2010, 9, 1055-1065J. Phys. Chem. C, 2008, 112 (7), pp 2476–2486
Williams2 Williams3
J. Phys. Chem. C, 2009, 113 (42), pp 18358–18368Photochem. Photobiol. Sci., 2010, 9, 1018-1026