Dresden 2017 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 70: Organic Electronics and Photovoltaics V: OPV (joint session CPP/DS/HL, organized by CPP)

CPP 70.7: Talk

Friday, March 24, 2017, 12:15–12:30, ZEU 255

Charge transfer recombination at planar hybrid inorganic/organic interfaces — •Ulrich Hörmann¹, Fortunato Piersimoni¹, Stefan Zeiske¹, Lukas Hoffmann², Thomas Riedl², and Dieter Neher¹ — ¹Universität Potsdam, Potsdam, Germany — ²Bergische Universität Wuppertal, Wuppertal, Germany

The role of the intermolecular energy gap in all-organic donor/acceptor heterojunction (HJ) solar cells is well established. In the case of hybrid inorganic/organic HJs the situation is less clear. Recently, Piersimoni et al. have shown that the energy of the hybrid charge transfer (HCT) emission in electroluminescence experiments correlates with the interface energetics determined by UPS and with the open circuit voltage (V_oc) of hybrid solar cells [1]. Here we focus on photovoltaic characterization of planar HJs between ZnO or SnO_x acceptor layers and different organic donor materials. Tools well established for all-organic solar cells are carefully transferred to these hybrid systems and their validity is confirmed. Reconstruction of the dark jV-curve from light intensity dependent measurement of V_oc and the short circuit current gets rid of the otherwise drastic influence of the series resistance in these devices and allows access to the ideality factor associated with the hybrid interface. Temperature dependent characterization in a carefully chosen operation regime allows the extraction of an effective energy gap, whose origin is – opposed to all-organic HJs – not completely clear, yet. With our combined analysis, we shed light on the nature of HCT states and their role for recombination at metal oxide/organic interfaces.

[1] Piersimoni et al. / Phys. Chem. Lett. 6, 500 (2015)