Intermediate-Sized Conjugated Donor Molecules for Organic Solar Cells: Comparison of Benzodithiophene and Benzobisthiazole-Based Cores
Parker, Timothy C.
Jucov, Evgheni V.
Timofeeva, Tatiana V.
Bazan, Guillermo C.
Blakey, Simon B.
Marder, Seth R.
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AbstractTwo intermediate-sized donor molecules, BBTz-X and BDT-X, have been synthesized by the Stille coupling between 4-(4,4-bis(2-ethylhexyl)-6-(trimethylstannyl)-4H-silolo[3,2-b:4,5-b′]dithiophen-2-yl)-7-(5′-hexyl-[2,2′-bithiophen]-5-yl)-[1,2,5]thiadiazolo[3,4-c]pyridine and either 4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)-2,6-diiodobenzo[1,2-d:4,5-d′]bis(thiazole) or 2,6-dibromo-4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-b:4,5-b′]dithiophene, respectively. Both oxidation and reduction potentials for BBTz-X are anodically shifted relative to those for BDT-X, but the oxidation potential is more sensitive to the identity of the core; this is consistent with what is seen for DFT-calculated HOMO and LUMO energies and with a slightly blue-shifted absorption maximum for BBTz-X. Although DFT calculations, along with crystal structures of related compounds, suggest more planar molecular structures for BBTz-X than for BDT-X, film structures and the effects of various annealing processes on these films, as revealed by GIWAXS, are similar. The performance of BDT-X:PC61BM bulk-heterojunction solar cells is more sensitive to annealing conditions than that of BBTz-X:PC61BM cells, but under appropriate conditions, both yield power conversion efficiencies of >7%.
CitationZhang S, Zhang J, Abdelsamie M, Shi Q, Zhang Y, et al. (2017) Intermediate-Sized Conjugated Donor Molecules for Organic Solar Cells: Comparison of Benzodithiophene and Benzobisthiazole-Based Cores. Chemistry of Materials 29: 7880–7887. Available: http://dx.doi.org/10.1021/acs.chemmater.7b02665.
SponsorsThe research was partly supported by the National Science Foundation, through the CCI Center for Selective C–H Functionalization (CHE-1205646 and CHE-1700982) and through the PREM program (DMR-1523611), and by the Department of the Navy, Office of Naval Research, through Award No. N00014-14-1-0580 (CAOP MURI).
PublisherAmerican Chemical Society (ACS)
JournalChemistry of Materials