46400 2018 eng 18705 18714 article ACS ACS 1 -- -- -- In this work, two novel donor/acceptor (D/A) complexes, namely, diindenoperylene (DIP)/1,3,4,5,7,8-hexafluoro-tetracyanonaphthoquinodimethane (F6TCNNQ) and alpha-sexithiophene (6T)/F6TCNNQ, are studied. The D/A complexes segregate in form of π−π stacked D/A cocrystals and can be observed by X-ray scattering. The different conformational degrees of freedom of the donor molecules, respectively, seem to affect the thin-film crystalline texture and composition of the D/A mixtures significantly. In equimolar mixtures, for DIP/F6TCNNQ, the crystallites are mostly uniaxially oriented and homogeneous, whereas for 6T/F6TCNNQ, a mostly 3D (isotropic) orientation of the crystallites and coexistence of domains of pristine compounds and D/A complex, respectively, are observed. Using optical absorption spectroscopy, we observe for each of the two mixed systems a set of new, strong transitions located in the near-IR range below the gap of the pristine compounds: such transitions are related to charge-transfer (CT) interactions between donor and acceptor. The optical anisotropy of domains of the D/A complexes with associated new electronic states is studied by ellipsometry. We infer that the CT-related transition dipole moment is perpendicular to the respective π-conjugated planes in the D/A complex. The Journal of Physical Chemistry C 10.1021/acs.jpcc.8b03744 31.10.2018 G. Duva L. Pithan C. Zeiser B. Reisz J. Dieterle B. Hofferberth P. Beyer L. Bogula A. Opitz Stefan Kowarik A. Hinderhofer A. Gerlach F. Schreiber eng uncontrolled Optical properties eng uncontrolled Molecular semiconductor eng uncontrolled X-ray diffraction Analytische Chemie Verlagsliteratur Datei im Netzwerk der BAM verfügbar ("Closed Access")