2,2-Dicyanovinyl-end-capped oligothiophenes as electron acceptor in solution processed bulk-heterojunction organic solar cells

Jianchang Wu, Yuchao Ma, Na Wu, Yi Lin, Jian Lin, Lilei Wang, Chang Qi Ma*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

36 Citations (Scopus)

Abstract

Abstract Three 2,2-dicyanovinyl (DCV) end-capped A-π-D-π-A type oligothiophenes (DCV-OTs) containing dithieno[3,2-b:2′,3′-d]silole (DTSi), cyclopenta[1,2-b:3,4-b′]dithiophene (DTCP) or dithieno[3,2-b:2′,3′-d]pyrrole (DTPy) unit as the central donor part, mono-thiophene as the π-conjugation bridge were synthesized. The absorption spectroscopies, cyclic voltammetry of these compounds were characterized. Results showed that all these compounds have intensive absorption band over 500-680 nm with a LUMO energy level around -3.80 eV, which is slightly higher than that of [6,6]phenyl-C61-butyric acid methyl ester (PC61BM, ELUMO = -4.01 eV), but lower than that of poly(3-hexylthiophene) (P3HT, ELUMO = -2.91 eV). Solution processed bulk heterojunction "all-thiophene" solar cells using P3HT as electron donor and the above mentioned oligothiophenes as electron acceptor were fabricated and tested. The highest power conversion efficiency (PCE) of 1.31% was achieved for DTSi-cored compound DTSi(THDCV)2, whereas PTB7:DTSi(THDCV)2 based device showed slightly higher PCE of 1.56%. Electron mobilities of these three compounds were measured to be around 10-5 cm2 V-1 s-1 by space charge limited current method, which is much lower than that of PC61BM, and was considered as one of the reason for the low photovoltaic performance.

Original languageEnglish
Article number3040
Pages (from-to)28-38
Number of pages11
JournalOrganic Electronics
Volume23
DOIs
Publication statusPublished - 1 Aug 2015

Keywords

  • "All-thiophene" solar cell
  • A-π-D-π-A type oligothiophenes
  • Non-fullerene acceptor
  • Organic solar cells
  • Structure-property relationship

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