New low band gap thieno[3,4-b]thiophene-based polymers with deep HOMO levels for organic solar cells

Download
  1. Get@NRC: New low band gap thieno[3,4-b]thiophene-based polymers with deep HOMO levels for organic solar cells (Opens in a new window)
DOIResolve DOI: http://doi.org/10.1039/c1jm11229e
AuthorSearch for: ; Search for: ; Search for: ; Search for: ; Search for: ; Search for: ; Search for: ; Search for:
TypeArticle
Journal titleJournal of Materials Chemistry
ISSN0959-9428
Volume21
Issue29
Pages1092010928; # of pages: 9
SubjectAlkoxy chains; Alkyl chain; Band gap energy; Bulk heterojunction solar cells; Electron acceptor; Electron donors; Electron-donating; Electronwithdrawing; Fluorine atoms; High power conversion; HOMO energy levels; Low band gap; Organic solar cell; Side-chains; Conversion efficiency; Electrons; Energy gap; Fluorine; Heterojunctions; Hole mobility; Ketones; Open circuit voltage; Organic polymers; Thiophene
AbstractTwo new soluble alternating alkyl-substituted benzo[1,2-b:4,5-b′] dithiophene and ketone-substituted thieno[3,4-b]thiophene copolymers were synthesized and characterized. We found that grafting 3-butyloctyl side chains to the benzo[1,2-b:4,5-b′]dithiophene unit at C4 and C8 afforded the resulting polymer (P1) a high hole mobility (∼10-2 cm2 Vs-1) and a low-lying HOMO energy level (5.22 eV). Preliminary experiments in bulk heterojunction solar cells using P1 as the electron donor demonstrated a high power conversion efficiency of 4.8% even with PC 61BM as the electron acceptor. The introduction of an electron-withdrawing fluorine atom into the thieno[3,4-b]thiophene unit at the C3 position (P2) lowers the HOMO energy level and consequently improves the open circuit voltage from 0.78 to 0.86 V. These values are about 0.1 V higher than those reported for their analogues based on alkoxy-substituted benzo[1,2-b:4,5-b′]dithiophene. This work demonstrates that the replacement of the alkoxy chains on the benzo[1,2-b:4,5-b′]dithiophene unit with less electron-donating alkyl chains is able to lower the HOMO energy levels of this class of polymers without increasing their band gap energy. © 2011 The Royal Society of Chemistry.
Publication date
LanguageEnglish
AffiliationNational Research Council Canada (NRC-CNRC); NRC Institute for Microstructural Sciences (IMS-ISM); NRC Institute for Chemical Process and Environmental Technology (ICPET-ITPCE)
Peer reviewedYes
NPARC number21271383
Export citationExport as RIS
Report a correctionReport a correction
Record identifier21de0e7e-79d7-40e8-affc-6374fd678f06
Record created2014-03-24
Record modified2016-05-09
Bookmark and share
  • Share this page with Facebook (Opens in a new window)
  • Share this page with Twitter (Opens in a new window)
  • Share this page with Google+ (Opens in a new window)
  • Share this page with Delicious (Opens in a new window)