Jump to main content
Jump to site search

Issue 6, 2011
Previous Article Next Article

Photochemical stability and photovoltaic performance of low-band gap polymers based on dithiophene with different bridging atoms

Author affiliations

Abstract

New low-band gap polymers based on dithienylbenzothiadiazole (DBT) and dithiophene with different bridging atoms have been synthesized and explored in a comparative study on the photochemical stability and photovoltaic performance. Two differently modified DBT units were exploited, namely 5,6-bis(tetradecyloxy)-4,7-di(thiophen-2-yl)benzo[c][1,2,5]thiadiazole (DBT1) and 4,7-bis(4-dodecylthiophen-2-yl)benzo[c][1,2,5]thiadiazole (DBT2). In thin films the polymers had optical band gaps in the range of 1.51–1.70 eV where the DBT2 based polymers are red shifted 61–81 nm compared to the DBT1 based polymers indicating greater interchain packing when the side chains are situated on the thienyl groups compared to on the benzothiadiazole unit. The best photovoltaic devices based on blends of polymer and [6,6]-phenyl C61butyric acid methyl ester (PCBM) were prepared with polymers based on the DBT1 unit giving efficiencies up to 2.3%. The photochemical stability was measured by the amount of absorbed photons under 1 sun versus the ageing time for each polymer, which clearly shows that the two polymers containing a 4,4-bis(2-ethylhexyl)-4H-cyclopenta[1,2-b:5,4-b′]dithiophene (CPDT) unit are by far the most unstable. Substitution of the bridging carbon atom with silicon results in a significant stability improvement by a factor 5.

Graphical abstract: Photochemical stability and photovoltaic performance of low-band gap polymers based on dithiophene with different bridging atoms

Back to tab navigation

Supplementary files

Publication details

The article was received on 14 Jan 2011, accepted on 03 Mar 2011 and first published on 28 Mar 2011


Article type: Paper
DOI: 10.1039/C1PY00017A
Citation: Polym. Chem., 2011,2, 1355-1361
  •   Request permissions

    Photochemical stability and photovoltaic performance of low-band gap polymers based on dithiophene with different bridging atoms

    M. Helgesen, T. J. Sørensen, M. Manceau and F. C. Krebs, Polym. Chem., 2011, 2, 1355
    DOI: 10.1039/C1PY00017A

Search articles by author

Spotlight

Advertisements