Regensburg 2010 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 62: Poster II: Photovoltaics and Organic Semiconductors

HL 62.18: Poster

Donnerstag, 25. März 2010, 18:00–20:00, Poster D2

The influence of the morphology of the active layer on inorganic/organic hybrid solar cells studied by electron spin resonance — •Florian Witt, Nicolay Radychev, Irina Lokteva, Joanna Kolny-Olesiak, Holger Borchert, and Jürgen Parisi — University of Oldenburg, Department of Physics, Energy and Semiconductor Research Laboratory (EHF), 26111 Oldenburg, Germany

In the last decade the method of exchanging the fullerene acceptors in organic bulk heterojunction solar cells by inorganic semiconducting nanocrystals has been studied to improve their performance. So far only few promising results in such structures, especially related to power conversion efficiencies, were achieved. One of the main factors for this lack of functionality is connected to the poor morphology in comparison pure organic cells. By consequence, the percolation pathways for charge transport are not well pronounced, and the interface area for charge carrier generation is reduced. It was shown that the generation of charge carriers on light excitation can be characterized by light induced electron spin resonance. With this technique the amount of long living polaron states in the donor polymer can be observed over time, with and without light excitation. This method is suitable to show the influence of the materials morphology to its charge generation and recombination dynamics. At deep temperatures also an analysis of polaron trap states in the material blends is possible. The results of comparative studies of P3HT/CdSe nanoparticle layers with different morphologies as well as of P3HT:PCBM blends will be presented.