Berlin 2012 – scientific programme
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 31: Organic semiconductors II
CPP 31.4: Talk
Thursday, March 29, 2012, 10:30–10:45, C 130
Blocking layer influence on Diindenoperylene based photovoltaic devices — •Andreas Steindamm1,2, Michael Brendel1,2, Katharina Topczak1, and Jens Pflaum1,2 — 1Exp. Phys. VI, Julius-Maximilians-University Würzburg, D-97074 Würzburg — 2ZAE Bayern e.V., D-97074 Würzburg
Diindenoperylene (DIP) has shown to be a suited donor material in combination with the acceptor C60 resulting in bilayer photovoltaic cells with open circuit voltages up to 0.9 V. Together with an exceptionally high fill factor of 74 % this yields an overall cell efficiency of around 4 % [1]. However, a severe drawback is the rather poor light absorption of the crystalline DIP layer due to the unfavorable orientation of transition dipoles along the surface normal, i.e. perpendicular to the electric field vector of the incident light. Therefore, harvesting of all photon-generated excitons is essential in these structures to achieve highest photocurrents possible. As a promising concept the application of exciton blocking layers (EBLs) has been suggested and will be addressed in this contribution by means of an intermediate Batho-Phenanthrolin (BPhen) EBL between the fullerene acceptor and the metallic cathode. As a main result, a doubling of the short circuit current (ISC) could be achieved by implementing the BPhen EBL. To identify the underlying effects, responsible for this enhancement, we employed photoluminescence (PL) quenching measurements which allow for separation of contributions caused by exciton reflection versus those related to metal penetration during depositon.
[1] A. Opitz, et al., IEEE J. Sel. Top. Quant. El. 16 (2010) 1707