Samenvatting
The optical properties of two sets of donor-acceptor-donor molecules with terminal bithiophene donor units and a central diketopyrrolopyrrole (DPP) acceptor unit are studied. The two sets differ in the alkyl chains on the DPP, which are either branched at the α-carbon (3-pentyl) (1-4) or linear (n-hexyl) (5-8). Within each set, the molecules differ by the absence or presence of n-hexyl chains on the terminal thiophene rings in the 3′, 4′, or 5′ positions. While in solution, the optical spectra differ only subtly; they differ dramatically in the solid state. In contrast to 5-8, 1-4 are nonplanar as a consequence of the sterically demanding 3-pentyl groups, which inhibit π-stacking of the DPP units. Using the crystal structures of 2 (brick layer stacking) and 6 (slipped stacking), we quantitatively explain the solid state absorption spectra. By computing the molecular transition charge density and solving the dispersion relation, the optical absorption of the molecules in the crystal is predicted and in agreement with experiments. For 2, a single resonance frequency is obtained, while for 6 two transitions are seen, with the lower-energy transition being less intense. The results demonstrate how subtle changes in substitution exert large effects in optical properties.
Originele taal-2 | Engels |
---|---|
Pagina's (van-tot) | 25229−25238 |
Aantal pagina's | 10 |
Tijdschrift | Journal of Physical Chemistry C |
Volume | 124 |
Nummer van het tijdschrift | 46 |
DOI's | |
Status | Gepubliceerd - 19 nov. 2020 |
Vingerafdruk
Duik in de onderzoeksthema's van 'Tuning the Optical Characteristics of Diketopyrrolopyrrole Molecules in the Solid State by Alkyl Side Chains'. Samen vormen ze een unieke vingerafdruk.Datasets
-
CCDC 2013158: Experimental Crystal Structure Determination
Meskers, S. C. J. (Bijdrager), Janssen, R. A. J. (Bijdrager), Saes, B. H. W. (Bijdrager), Lutz, M. (Bijdrager) & Wienk, M. M. (Bijdrager), Cambridge Crystallographic Data Centre, 30 jun. 2020
DOI: 10.5517/ccdc.csd.cc25kvl6
Dataset
-
CCDC 2013159: Experimental Crystal Structure Determination
Meskers, S. C. J. (Bijdrager), Janssen, R. A. J. (Bijdrager), Saes, B. H. W. (Bijdrager), Lutz, M. (Bijdrager) & Wienk, M. M. (Bijdrager), Cambridge Crystallographic Data Centre, 30 jun. 2020
DOI: 10.5517/ccdc.csd.cc25kvm7, http://www.ccdc.cam.ac.uk/services/structure_request?id=doi:10.5517/ccdc.csd.cc25kvm7&sid=DataCite
Dataset