SKM 2023 – scientific programme
Parts | Days | Selection | Search | Updates | Downloads | Help
CPP: Fachverband Chemische Physik und Polymerphysik
CPP 1: Focus: Organic Solar Cells Based on Non-fullerene Acceptors: Loss Mechanism and Options for Above 20 % Efficiencies I
CPP 1.11: Talk
Monday, March 27, 2023, 12:45–13:00, GÖR 226
Power-law density of states in organic solar cells revealed by the open-circuit voltage dependence of the ideality factor — •Maria Saladina1, Christopher Wöpke1, Clemens Göhler1, Ivan Ramirez2, Olga Gerdes2, Chao Liu3,4, Ning Li3,4,5, Thomas Heumüller3,4, Christoph J. Brabec3,4, Karsten Walzer2, Martin Pfeiffer2, and Carsten Deibel1 — 1Technische Universität Chemnitz, Germany — 2Heliatek GmbH, Germany — 3FAU Erlangen-Nürnberg, Germany — 4Helmholtz Institute Erlangen-Nürnberg for Renewable Energy, Germany — 5South China University of Technology, China
We determine the density of states (DOS) in disordered semiconductors via the diode ideality factor (nid). We employ illumination intensity and temperature-dependent open-circuit voltage measurements. In amorphous silicon, we found that nid only depends on the temperature, and can be explained by an exponential DOS distribution.
For the organic donor-acceptor solar cells, we find that nid is not only temperature but also light intensity-dependent. The seemingly unsystematic dependence of nid on the light intensity becomes systematic once the former is displayed in dependence of the open-circuit voltage, which is a means to sample the DOS distribution at a certain energetic depth. This evaluation approach leads to our central result: the DOS follows a power-law distribution over a broad range of energies. In particular, for the investigated organic solar cells under working conditions the DOS is best represented by the power-law, not a gaussian or exponential one.