Regensburg 2010 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 62: Poster II: Photovoltaics and Organic Semiconductors

HL 62.23: Poster

Thursday, March 25, 2010, 18:00–20:00, Poster D2

Influence of pyridine treatment on the ligand shell of OA-capped CdSe nanoparticles and the impact on polymer/CdSe hybrid solar cells — •Irina Lokteva, Nikolay Radychev, Holger Borchert, Jürgen Parisi, and Joanna Kolny-Olesiak — University of Oldenburg, Oldenburg, Germany

This study describes the surface modification of the original oleic acid (OA) capped CdSe colloidal quantum dots (QDs) with pyridine molecules and application of the pyridine coated CdSe QDs for the preparation of polymer/CdSe hybrid solar cells.

The composition of the ligand shell was investigated by means of nuclear magnetic resonance (NMR) spectroscopy and thermal gravimetric analysis (TGA). It was shown that after one-fold pyridine treatment some amount of OA was still present in the sample, which motivated us to fulfil repeated steps of the ligand exchange. The absorption spectra after repeated pyridine treatment revealed that no aggregation or oxidation of the nanoparticles in solution occurred. TEM images were used as well to characterize the successive steps of the ligand exchange.

The hybrid CdSe-P3HT solar cells were fabricated using the pyridine capped CdSe QDs and I-V characteristics of these solar cells were collected to characterize the sequential steps of the pyridine treatment. Although repeated ligand exchange was found to have a beneficial effect in the sense that they led to more complete ligand exchange which in turn enabled more efficient charge transfer, the main characteristic parameters of the solar cells were found to deteriorate. Correlations of this behavior with the morphology of the hybrid blends were analyzed.