Regensburg 2016 – scientific programme
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O: Fachverband Oberflächenphysik
O 65: Organic Photovoltaics and Electronics
O 65.6: Talk
Wednesday, March 9, 2016, 16:15–16:30, H2
Passivation and modification of silicon nanowires towards hybrid solar cells — •Jessica Hänisch1, Carola Klimm1, Marc A. Gluba1, Karsten Hinrichs2, Iver Lauermann3, Wolfram Calvet3, Norbert H. Nickel1, and Jörg Rappich1 — 1Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Institut für Silizium-Photovoltaik, Berlin, Germany — 2ISAS e.V. - Leibniz-Institut für Analytische Wissenschaften, Berlin, Germany — 3BESSY, Berlin, Germany
Hybrid solar cells combine inorganic and organic materials to benefit from both areas, particularly in terms of production costs and material consumption. The inorganic-organic interface needs to be well passivated, especially if nanowires with a high surface area are implemented to enhance light absorption. The silicon nanowires were prepared by metal assisted chemical etching (MACE). The etching procedure leads to surface damaging and thereby generates surface defects. These defects reside in the band gap and act as recombination centers. As a consequence, the amount of collected charge carriers is reduced and therefore, the power conversion efficiency decreases. We applied electropolishing procedures to the silicon surface to minimize the amount of surface defects. Changes in the density of surface defects were directly monitored by in-situ photoluminescence measurements. To preserve the improved surface passivation obtained after the electropolishing process we used (electro-)chemical grafting of small molecules and investigated the surfaces by infrared spectroscopy, x-ray photoelectron spectroscopy and photoluminescence measurements.