Journal Article

FZJ-2022-04716

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Formation of Crystalline Bulk Heterojunctions in Organic Solar Cells: Insights from Phase-Field Simulations

Ronsin, O. J. J. (Corresponding author)FZJ* ; Harting, J.FZJ*

2022
Soc. Washington, DC

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Please use a persistent id in citations: http://hdl.handle.net/2128/33807  doi:10.1021/acsami.2c14319

Abstract: The performance of organic solar cells strongly depends on thebulk-heterojunction (BHJ) morphology of the photoactive layer. This BHJforms during the drying of the wet-deposited solution, because of physicalprocesses such as crystallization and/or liquid-liquid phase separation (LLPS).However, the process-structure relationship remains insufficiently understood.In this work, a recently developed, coupled phase-field−fluid mechanicsframework is used to simulate the BHJ formation upon drying. For the firsttime, this allows to investigate the interplay between all the relevant physicalprocesses (evaporation, crystal nucleation and growth, liquid demixing,composition-dependent kinetic properties), within a single coherent theoreticalframework. Simulations for the model system P3HT-PCBM are presented. Thecomparison with previously reported in situ characterization of the drying structure is very convincing: The morphology formationpathways, crystallization kinetics, and final morphology are in line with experimental results. The final BHJ morphology is a subtlemixture of pure crystalline donor and acceptor phases, pure and mixed amorphous domains, which depends on the processparameters and material properties. The expected benefit of such an approach is to identify physical design rules for ink formulationand processing conditions to optimize the cell’s performance. It could be applied to recent organic material systems in the future.

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Contributing Institute(s):

1. Helmholtz-Institut Erlangen-Nürnberg Erneuerbare Energien (IEK-11)

Research Program(s):

1. 1215 - Simulations, Theory, Optics, and Analytics (STOA) (POF4-121) (POF4-121)
2. DFG project 449539983 - Prozess-Struktur Relationen für die lösungsmittelbasierte organische Photovoltaik (449539983)

Appears in the scientific report 2022

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Database coverage:
; ; Clarivate Analytics Master Journal List ; Current Contents - Engineering, Computing and Technology ; Current Contents - Physical, Chemical and Earth Sciences ; Essential Science Indicators ; IF >= 5 ; JCR ; SCOPUS ; Science Citation Index Expanded ; Web of Science Core Collection

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