SKM 2023 – scientific programme

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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 1.7: Invited Talk

Monday, March 27, 2023, 11:30–12:00, GÖR 226

Lost in translation? Transport resistance in organic solar cells — •Carsten Deibel — Institut für Physik, Technische Universität Chemnitz, 09126 Chemnitz, Germany

With the advent of non-fullerene acceptors, breaking the 20 % power conversion efficiency limit is within close reach for organic solar cells. Understanding the efficiency-limiting processes remains important.

I will discuss how losses in the fill factor can be due to the transport resistance, a voltage loss because of a low conductivity in the active layer. Its relevance for organic solar cells was only shown a half dozen years ago [1]. I will present transport resistance limiting different organic solar cell types, and then focus on fresh and thermally degraded PM6:Y6 solar cells (heated to 85^∘C, in the dark, under nitrogen atmosphere), a state-of-the-art system based on the non-fullerene Y6. The increasing fill factor losses on this degradation path are because of the transport resistance [2]. The reason seems to be trap formation in the tail states, which decrease the active layer conductivity.

U. Würfel, D. Neher, A. Spies, S. Albrecht, Nat. Commun. 6, 6951 (2015).
C. Wöpke, C. Göhler, M. Saladina, X. Du, L. Nian, C. Greve, C. Zhu, K. M. Yallum, Y. J. Hofstetter, D. Becker-Koch, N. Li, T. Heumüller, I. Milekhin, D. R. T. Zahn, C. J. Brabec, N. Banerji, Y. Vaynzof, E. M. Herzig, R. C. I. MacKenzie, C. Deibel. Nat. Commun. 13, 3786 (2022).