Novel high band gap pendant-borylated carbazole polymers with deep HOMO levels through direct +N=B- interaction for organic photovoltaics

Rasmus G. Brandt, Steffen G. Sveegaard, Manjun Xiao, Wei Yue, Zhengkun Du, Meng Qiu, Dechan Angmo, Thomas Rieks Andersen, Frederik C Krebs, Renqiang Yang, Donghong Yu

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Abstract

In this communication, we investigate the direct and still conjugated intramolecular +N=B- interactions in novel high band gap borylated carbazole containing polymers, namely, poly(3,6-(N-di(2,4,6-trimethyl)-phenylboryl-carbazole)-alt- 4,8-di(5-(2-ethylhexyl)thiophene-2-yl)benzo[1,2-b: 4,5-b'] dithiophene) (P(3,6-BCBDT)) and poly(3,6-(N-di(2,4,6-trimethyl)phenylboryl-carbazole)-alt-3,3 '''- didodecyl-2,2': 5',2 '': 5 '',2 '''-quaterthiophene) (P(3,6-BCQT)), which result in ambipolarity, high electron affinity, and deep HOMO levels. The quasi-donor-acceptor nature of the two polymers was confirmed by UV-Vis absorption, electro-chemical property studies, and computer modelling. Band gaps of 2.07 eV for P(3,6-BCBDT) and 2.23 eV for P(3,6-BCQT) were obtained. P(3,6-BCQT) afforded a power conversion efficiency of 1.44%, with a Jsc of 4.82 mA cm-2, a Voc of 0.79 V and a FF of 37%, and P(3,6-BCBDT) performed better with an efficiency of 3.82%, with a Jsc of 8.31 mA cm-2, a V-oc of 1.0 V based on its low lying HOMO level, and a FF of 45%.
Original languageEnglish
JournalJournal of Materials Chemistry C
Volume4
Issue number20
Pages (from-to)4393-4401
Number of pages9
ISSN2050-7526
DOIs
Publication statusPublished - 2016

Cite this

Brandt, R. G., Sveegaard, S. G., Xiao, M., Yue, W., Du, Z., Qiu, M., Angmo, D., Andersen, T. R., Krebs, F. C., Yang, R., & Yu, D. (2016). Novel high band gap pendant-borylated carbazole polymers with deep HOMO levels through direct +N=B- interaction for organic photovoltaics. Journal of Materials Chemistry C, 4(20), 4393-4401. https://doi.org/10.1039/c6tc01208f