Favorable Mixing Thermodynamics in Ternary Polymer Blends for Realizing High Efficiency Plastic Solar Cells

Gasparini N, Kahmann S, Salvador MF, Perea JD, Sperlich A, Baumann A, Li N, Rechberger S, Spiecker E, Dyakonov V, Portale G, Loi MA, Brabec C, Ameri T (2019)

Publication Language: English

Publication Status: Published

Publication Type: Journal article, Original article

Publication year: 2019

Journal

Publisher: Wiley-VCH Verlag

Book Volume: 9

Article Number: 1803394

Journal Issue: 19

DOI: 10.1002/aenm.201803394

Abstract

Ternary blends with broad spectral absorption have the potential to increase charge generation in organic solar cells but feature additional complexity due to limited intermixing and electronic mismatch. Here, a model system comprising the polymers poly[5,5-bis(2-butyloctyl)-(2,2-bithiophene)-4,4-dicarboxylate-alt-5,5-2,2-bithiophene] (PDCBT) and PTB7-Th and PC70BM as an electron accepting unit is presented. The power conversion efficiency (PCE) of the ternary system clearly surpasses the performance of either of the binary systems. The photophysics is governed by a fast energy transfer process from PDCBT to PTB7-Th, followed by electron transfer at the PTB7-Th:fullerene interface. The morphological motif in the ternary blend is characterized by polymer fibers. Based on a combination of photophysical analysis, GIWAXS measurements and calculation of the intermolecular parameter, the latter indicating a very favorable molecular affinity between PDCBT and PTB7-Th, it is proposed that an efficient charge generation mechanism is possible because PTB7-Th predominantly orients around PDCBT filaments, allowing energy to be effectively relayed from PDCBT to PTB7-Th. Fullerene can be replaced by a nonfullerene acceptor without sacrifices in charge generation, achieving a PCE above 11%. These results support the idea that thermodynamic mixing and energetics of the polymer–polymer interface are critical design parameter for realizing highly efficient ternary solar cells with variable electron acceptors

Authors with CRIS profile

Additional Organisation(s)

Involved external institutions

University of Groningen / Rijksuniversiteit Groningen Netherlands (NL) Julius-Maximilians-Universität Würzburg Germany (DE) Bayerisches Zentrum für Angewandte Energieforschung e.V. (ZAE Bayern) Germany (DE)

How to cite

APA:

Gasparini, N., Kahmann, S., Salvador, M.F., Perea, J.D., Sperlich, A., Baumann, A.,... Ameri, T. (2019). Favorable Mixing Thermodynamics in Ternary Polymer Blends for Realizing High Efficiency Plastic Solar Cells. Advanced Energy Materials, 9(19). https://doi.org/10.1002/aenm.201803394

MLA:

Gasparini, Nicola, et al. "Favorable Mixing Thermodynamics in Ternary Polymer Blends for Realizing High Efficiency Plastic Solar Cells." Advanced Energy Materials 9.19 (2019).

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