Details

Autor(en) / Beteiligte

• Krebs, Frederik C.
• Spanggaard, Holger

Titel

Antibatic photovoltaic response in zinc-porphyrin-linked oligothiophenes

Ist Teil von

• Solar energy materials and solar cells, 2005-09, Vol.88 (4), p.363-375

Ort / Verlag

Amsterdam: Elsevier B.V

Erscheinungsjahr

2005

Quelle

Access via ScienceDirect (Elsevier)

Beschreibungen/Notizen

• We present the synthesis of oligohexylthiophenes starting from 3, 4′-dihexyl-[2, 2′]bithiophene ( 1) 3, 4′, 4″, 4‴-tetrahexyl-[2, 2′; 5′, 2″; 5″, 2‴]quarterthiophene ( 2), 3, 4′, 4″, 4‴, 4⁗, 4′′′′′, 4′′′′′′, 4′′′′′′′-octahexyl-[2, 2′; 5′, 2″; 5″, 2‴; 5‴, 2⁗; 5⁗, 2′′′′′; 5′′′′′, 2′′′′′′; 5′′′′′′, 2′′′′′′′]octithiophene ( 3) and 3, 4′, 4″, 4‴, 4⁗, 4′′′′′, 4′′′′′′, 4′′′′′′′, 4′′′′′′′′, 4′′′′′′′′′, 4′′′′′′′′′′, 4′′′′′′′′′′′, 4′′′′′′′′′′′′, 4′′′′′′′′′′′′′, 4′′′′′′′′′′′′′′, 4′′′′′′′′′′′′′′′-hexadecahexyl-[2, 2′; 5′, 2″; 5″, 2‴; 5‴, 2⁗; 5⁗, 2′′′′′; 5′′′′′, 2′′′′′′; 5′′′′′′, 2′′′′′′′; 5′′′′′′′, 2′′′′′′′′; 5′′′′′′′′, 2′′′′′′′′′; 5′′′′′′′′′, 2′′′′′′′′′′; 5′′′′′′′′′′, 2′′′′′′′′′′′; 5′′′′′′′′′′′, 2′′′′′′′′′′′′; 5′′′′′′′′′′′′, 2′′′′′′′′′′′′′; 5′′′′′′′′′′′′′, 2′′′′′′′′′′′′′′; 5′′′′′′′′′′′′′′, 2′′′′′′′′′′′′′′′]hexadecathiophene ( 4) by regioselective bromination using N-bromosuccinimide and regioselective lithiation using lithiumdiisopropylamide in ethylbenzene/THF/heptane followed by reaction with trimethylstannylchloride and subsequent palladium catalysed Stille coupling. We further synthesised 5,15-bis(3, 4′, 4″, 4‴, 4⁗, 4′′′′′, 4′′′′′′, 4′′′′′′′-octahexyl-[2, 2′; 5′, 2″; 5″, 2‴; 5‴, 2⁗; 5⁗, 2′′′′′; 5′′′′′, 2′′′′′′; 5′′′′′′, 2′′′′′′′]octithiophene-5-yl)-10, 20-bis(3, 5-ditertbutylphenyl)zinc(II)porphyrin ( 5) from trimethyl(3, 4′, 4″, 4‴, 4⁗, 4′′′′′, 4′′′′′′, 4′′′′′′′-Octahexyl-[2, 2′; 5′, 2″; 5″; 2‴; 5‴, 2⁗; 5⁗, 2′′′′′; 5′′′′′, 2′′′′′′; 5′′′′′′, 2′′′′′′′]octithiophene-5-yl)stannane ( 3-SnMe 3 ) and 5, 15-dibromo-10, 20-bis(3, 5-ditertbutylphenyl)zinc(II)porphyrin ( 6) by Stille coupling. All the products were characterised by size exclusion chromatography (SEC), NMR, MALDI-TOF and elemental analysis and purified by preparative SEC before subjecting them to photophysical studies. UV–vis and emission spectroscopy were used to determine quantum yields and energy transfer. The photon balance was established and used to rationalise the photovoltaic behaviour of 4 and 5. While 4 gave rise to photovoltaic devices giving a moderate photovoltaic response that was symbatic with the absorption spectrum, 5 showed a photovoltaic response that was antibatic with a part of the absorption spectrum of the zinc-porphyrin constituent. We ascribe this behaviour to efficient internal conversion of the energy absorbed by (and the energy transferred to) the zinc-porphyrin constituent.