Dresden 2006 – scientific programme
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CPP: Chemische Physik und Polymerphysik
CPP 23: POSTER Functional Organic Thin Films
CPP 23.53: Poster
Thursday, March 30, 2006, 17:00–19:00, P2
Exciplex dynamics in a M3EH-PPV:CN-Ether-PPV blend film and a D-A block copolymer film — •Chunhong Yin1, Th. Kietzke1,2, H.H. Hörhold3, and D. Neher1 — 1Am Neuen Palais 10, 14469 Potsdam — 2Institute of Materials Research and Engineering (IMRE), Research Link 3, Singapore — 3University of Jena , Institute of Organic Chemistry and Macromolecular, Chemistry, Humboldtstr.10, 07743 Jena
Solar cells based on semiconducting polymers have attracted a lot of interest. However, currently the efficiencies of polymer-based solar cells are still lower than the values obtained from their inorganic counterparts. Here, we demonstrate efficient charge carrier recombination via exciplex emission in blends of M3EH-PPV and CN-Ether-PPV. We also show that the intensity of exciplex emission is significantly reduced upon annealing. At the same time, the corresponding solar cell efficiency increases largely. We attribute the improvement of solar cell efficiency to partial de-mixing of the polymer components. Apparently, charge carrier recombination via exciplex formation constitutes one of the loss channels which limits the efficiency of solar cells based on these polymers. In addition, a statistical D-A block copolymer, which can be considered as a model system of an ultra fine blend, was studied. In this case, the intensity of exciplex emission and the solar cell efficiency was only weakly altered upon annealing, indication that the significant changes observed for the blends are due to morphological effects.
Reference: Th. Kietzke, H.-H. Hörhold, D. Neher, Chem. Matter, in press