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.
organic electronics
polimorphism
non-fullerene acceptors
organic solar cells
organic semiconductors
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
Institut de Ciència de Materials de Barcelona (ICMAB-CSIC)
Amaia Iturrospe
Centro de Física de Materiales (CSIC-UPV/EHU)
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
Centro de Física de Materiales (CSIC-UPV/EHU)
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
Institut de Ciència de Materials de Barcelona (ICMAB-CSIC)
Christian Müller
Chalmers, Kemi och kemiteknik, Tillämpad kemi
Daniele Cangialosi
Centro de Física de Materiales (CSIC-UPV/EHU)
Natalie Stingelin
Georgia Institute of Technology
Université de Bordeaux
Jaime Martin
Basque Foundation for Science (Ikerbasque)
Universidade da Coruña
Universidad del Pais Vasco / Euskal Herriko Unibertsitatea
Advanced Functional Materials
1616-301X (ISSN) 16163028 (eISSN)
Vol. 31 29 2103784Ämneskategorier
Materialkemi
Annan fysik
Den kondenserade materiens fysik
DOI
10.1002/adfm.202103784