Understanding and Controlling the Evolution of Nanomorphology and Crystallinity of Organic Bulk-Heterojunction Blends with Solvent Vapor Annealing

Harreiß C, Langner S, Wu M, Berlinghof M, Rechberger S, Will J, Conroy M, Bangert U, Unruh T, Brabec C, Spiecker E (2022)

Publication Type: Journal article

Publication year: 2022

Journal

Solar RRL Wiley-VCH

DOI: 10.1002/solr.202200127

Abstract

Solvent vapor annealing (SVA) has been shown to significantly improve the device performance of organic bulk-heterojunction solar cells, yet the mechanisms linking nanomorphology, crystallinity of the active layer, and performance are still largely missing. Here, the mechanisms are tackled by correlating the evolution of nanomorphology, crystallinity, and performance with advanced transmission electron microscopy methods systematically. Model system of DRCN5T:PC71BM blends are SVA treated with four solvents differing in their donor and acceptor solubilities. The choice of solvent drastically influences the rate at which the maximum device efficiency establishes, though similar values can be achieved for all solvents. The donor solubility is identified as a key parameter that controls the kinetics of diffusion and crystallization of the blend molecules, resulting in an inverse relationship between optimal annealing time and donor solubility. For the highest efficiency, optimum domain size and single-crystalline nature of DRCN5T fibers are found to be crucial. Moreover, the π–π stacking orientation of the crystallites is directly revealed and related to the nanomorphology, providing insight into the charge carrier transport pathways. Finally, a qualitative model relating morphology, crystallinity, and device efficiency evolution during SVA is presented, which may be transferred to other light-harvesting blends.

Authors with CRIS profile

Christina Harreiß Lehrstuhl für Werkstoffwissenschaften (Mikro- und Nanostrukturforschung) Stefan Langner Institute Materials for Electronics and Energy Technology (i-MEET) (i-MEET) Mingjian Wu Lehrstuhl für Werkstoffwissenschaften (Mikro- und Nanostrukturforschung) Marvin Berlinghof Lehrstuhl für Kristallographie und Strukturphysik (ICSP) Stefanie Rechberger Lehrstuhl für Werkstoffwissenschaften (Mikro- und Nanostrukturforschung) Johannes Will Lehrstuhl für Werkstoffwissenschaften (Mikro- und Nanostrukturforschung) Tobias Unruh Professur für Nanomaterialcharakterisierung (Streumethoden) Christoph Brabec Institute Materials for Electronics and Energy Technology (i-MEET) (i-MEET) Erdmann Spiecker Lehrstuhl für Werkstoffwissenschaften (Mikro- und Nanostrukturforschung)

Additional Organisation(s)

Graduiertenkolleg 1896/2 In situ Mikroskopie mit Elektronen, Röntgenstrahlen und Rastersonden Lehrstuhl für Werkstoffwissenschaften (Mikro- und Nanostrukturforschung) Interdisziplinäres Zentrum, Center for Nanoanalysis and Electron Microscopy (CENEM)

Related research project(s)

In-situ Characterization of Nanomaterials with Electrons, X-rays/Neutrons and Scanning Probes (GRK 1896) Oct. 1, 2013 - Sept. 30, 2022

Involved external institutions

University of Limerick IE Ireland (IE)

How to cite

APA:

Harreiß, C., Langner, S., Wu, M., Berlinghof, M., Rechberger, S., Will, J.,... Spiecker, E. (2022). Understanding and Controlling the Evolution of Nanomorphology and Crystallinity of Organic Bulk-Heterojunction Blends with Solvent Vapor Annealing. Solar RRL. https://doi.org/10.1002/solr.202200127

MLA:

Harreiß, Christina, et al. "Understanding and Controlling the Evolution of Nanomorphology and Crystallinity of Organic Bulk-Heterojunction Blends with Solvent Vapor Annealing." Solar RRL (2022).

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