Polymorphism in Non-Fullerene Acceptors Based on Indacenodithienothiophene
Artikel i vetenskaplig tidskrift, 2021
Organic solar cells incorporating non-fullerene acceptors (NFAs) have reached remarkable power conversion efficiencies of over 18%. Unlike fullerene derivatives, NFAs tend to crystallize from solutions, resulting in bulk heterojunctions that include a crystalline acceptor phase. This must be considered in any morphology-function models. Here, it is confirmed that high-performing solution-processed indacenodithienothiophene-based NFAs, i.e., ITIC and its derivatives ITIC-M, ITIC-2F, and ITIC-Th, exhibit at least two crystalline forms. In addition to highly ordered polymorphs that form at high temperatures, NFAs arrange into a low-temperature metastable phase that is readily promoted via solution processing and leads to the highest device efficiencies. Intriguingly, the low-temperature forms seem to feature a continuous network that favors charge transport despite of a poorly order along the pi-pi stacking direction. As the optical absorption of the structurally more disordered low-temperature phase can surpass that of the more ordered polymorphs while displaying comparable-or even higher-charge transport properties, it is argued that such a packing structure is an important feature for reaching highest device efficiencies, thus, providing guidelines for future materials design and crystal engineering activities.
polimorphism
organic solar cells
organic semiconductors
organic electronics
non-fullerene acceptors
Författare
Sara Marina
Universidad del Pais Vasco / Euskal Herriko Unibertsitatea
Alberto D. Scaccabarozzi
Istituto Italiano di Tecnologia
King Abdullah University of Science and Technology (KAUST)
Edgar Gutierrez-Fernandez
Universidad del Pais Vasco / Euskal Herriko Unibertsitatea
Eduardo Solano
El Sincrotrón ALBA
Aditi Khirbat
Georgia Institute of Technology
Laura Ciammaruchi
Consejo Superior de Investigaciones Científicas (CSIC)
Amaia Iturrospe
Consejo Superior de Investigaciones Científicas (CSIC)
Alex Balzer
Georgia Institute of Technology
Liyang Yu
Chalmers, Kemi och kemiteknik, Tillämpad kemi
Elena Gabirondo
Universidad del Pais Vasco / Euskal Herriko Unibertsitatea
Xavier Monnier
Donostia International Physics Center
Consejo Superior de Investigaciones Científicas (CSIC)
Haritz Sardon
Universidad del Pais Vasco / Euskal Herriko Unibertsitatea
Thomas D. Anthopoulos
King Abdullah University of Science and Technology (KAUST)
Mario Caironi
Istituto Italiano di Tecnologia
Mariano Campoy-Quiles
Consejo Superior de Investigaciones Científicas (CSIC)
Christian Müller
Chalmers, Kemi och kemiteknik, Tillämpad kemi
Daniele Cangialosi
Consejo Superior de Investigaciones Científicas (CSIC)
Natalie Stingelin
Université de Bordeaux
Georgia Institute of Technology
Jaime Martin
Universidad del Pais Vasco / Euskal Herriko Unibertsitatea
Universidade da Coruña
Basque Foundation for Science (Ikerbasque)
Advanced Functional Materials
1616-301X (ISSN) 16163028 (eISSN)
Vol. 31 29 2103784Ämneskategorier (SSIF 2011)
Materialkemi
Annan fysik
Den kondenserade materiens fysik
DOI
10.1002/adfm.202103784