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Organic single crystals of charge-transfer complexes: model systems for the study of donor/acceptor interactions



Katelyn Goetz, Hamna Iqbal, Emily Bittle, Christina Hacker, Sujitra Pookpanratana, Oana Jurchescu


The charge-transfer (CT) state arising as a hybrid electronic state at the interface between charge donor and charge acceptor molecular units is important to a wide variety of physical processes in organic semiconductor devices. The exact nature of this state depends heavily on the nature and co-facial overlap between the donor and acceptor; however, altering this overlap is usually accompanied by extensive confounding variations in properties due to extrinsic factors, such as microstructure. As a consequence, establishing reliable relationships between donor/acceptor molecular structure, their molecular overlap, degree of charge transport and physical properties, is challenging. Herein, we examine the electronic structure of a polymorph system based on the donor dibenzotetrathiafulvalene (DBTTF) and the acceptor 7,7,8,8-tetracyanoquinodimethane (TCNQ) in the form of high-quality single crystals varying in the donor-acceptor overlap. Using angle-resolved photoemission spectroscopy, we resolve the highest occupied molecular orbital states of the CT crystals. Analysis based on field-effect transistors allows us to probe the sub-gap states impacting hole and electron transport. Our results expand the understanding on the impact of donor and acceptor interactions on electronic structure and charge transport.
Materials Horizons


Goetz, K. , Iqbal, H. , Bittle, E. , Hacker, C. , Pookpanratana, S. and Jurchescu, O. (2021), Organic single crystals of charge-transfer complexes: model systems for the study of donor/acceptor interactions, Materials Horizons, [online],, (Accessed March 2, 2024)
Created October 15, 2021, Updated November 29, 2022