title: Inverted bulk-heterojunction solar cell with cross-linked hole-blocking layer.
abstract: We have developed a hole-blocking layer for bulk-heterojunction solar cells based on cross-linked polyethylenimine (PEI). We tested five different ether-based cross-linkers and found that all of them give comparable solar cell efficiencies. The initial idea that a cross-linked layer is more solvent resistant compared to a pristine PEI layer could not be confirmed. With and without cross-linking, the PEI layer sticks very well to the surface of the indium-tin-oxide electrode and cannot be removed by solvents used to process PEI or common organic semiconductors. The cross-linked PEI hole-blocking layer functions for multiple donor-acceptor blends. We found that using cross-linkers improves the reproducibility of the device fabrication process.
authors.affiliation: Institute for Organic Solar Cells, Johannes Kepler University Linz, Altenbergerstrasse 69, 4040 Linz, Austria ; Institute of Science and Technology, Department of Advanced Technologies, Gazi University, 06570 Ankara, Turkey.
authors.forename: Yasemin
authors.initials: Y
authors.lastname: Udum
authors.affiliation: Institute for Organic Solar Cells, Johannes Kepler University Linz, Altenbergerstrasse 69, 4040 Linz, Austria.
authors.forename: Patrick
authors.initials: P
authors.lastname: Denk
authors.affiliation: Institute for Organic Solar Cells, Johannes Kepler University Linz, Altenbergerstrasse 69, 4040 Linz, Austria.
authors.forename: Getachew
authors.initials: G
authors.lastname: Adam
authors.affiliation: Institute for Organic Solar Cells, Johannes Kepler University Linz, Altenbergerstrasse 69, 4040 Linz, Austria.
authors.forename: Dogukan H
authors.initials: DH
authors.lastname: Apaydin
authors.affiliation: Institute of Physics, Montanuniversitaet Leoben, Franz-Josef-Straße 18, 8700 Leoben, Austria.
authors.forename: Andreas
authors.initials: A
authors.lastname: Nevosad
authors.affiliation: Institute of Physics, Montanuniversitaet Leoben, Franz-Josef-Straße 18, 8700 Leoben, Austria.
authors.forename: Christian
authors.initials: C
authors.lastname: Teichert
authors.affiliation: Institute for Organic Solar Cells, Johannes Kepler University Linz, Altenbergerstrasse 69, 4040 Linz, Austria.
authors.forename: Matthew
authors.initials: M
authors.lastname: S White
authors.affiliation: Institute for Organic Solar Cells, Johannes Kepler University Linz, Altenbergerstrasse 69, 4040 Linz, Austria.
authors.forename: Niyazi
authors.initials: N
authors.lastname: S Sariciftci
authors.affiliation: Institute for Organic Solar Cells, Johannes Kepler University Linz, Altenbergerstrasse 69, 4040 Linz, Austria.
authors.forename: Markus C
authors.initials: MC
authors.lastname: Scharber
keywords: Device design; Electrical contact; Organic solar cell; Stability