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Title: Furan Substituted Diketopyrrolopyrrole and Thienylenevinylene Based Low Band Gap Copolymer for High Mobility Organic Thin Film Transistors

Journal Article · · Journal of Materials Chemistry
DOI:https://doi.org/10.1039/c2jm32376a· OSTI ID:1047635
 [1];  [2];  [3];  [2];  [4];  [1];  [3];  [3];  [3]
  1. Institute of Materials Research and Engineering (IMRE), Agency for Science, Technology, and Research
  2. National University of Singapore (NUS)
  3. National University of Singapore
  4. ORNL

A novel solution processable donor-acceptor (D-A) based low band gap polymer semiconductor poly{l_brace}3,6-difuran-2-yl-2,5-di(2-octyldodecyl)-pyrrolo[3,4-c]pyrrole-1,4-dione-alt-thienylenevinylene{r_brace} (PDPPF-TVT), was designed and synthesized by a Pd-catalyzed Stille coupling route. An electron deficient furan based diketopyrrolopyrrole (DPP) block and electron rich thienylenevinylene (TVT) donor moiety were attached alternately in the polymer backbone. The polymer exhibited good solubility, film forming ability and thermal stability. The polymer exhibits wide absorption bands from 400 nm to 950 nm (UV-vis-NIR region) with absorption maximum centered at 782 nm in thin film. The optical band gap (E{sub g}{sup opt}) calculated from the polymer film absorption onset is around 1.37 eV. The {pi}-energy band level (ionization potential) calculated by photoelectron spectroscopy in air (PESA) for PDPPF-TVT is around 5.22 eV. AFM and TEM analyses of the polymer reveal nodular terrace morphology with optimized crystallinity after 200 C thermal annealing. This polymer exhibits p-channel charge transport characteristics when used as the active semiconductor in organic thin-film transistor (OTFT) devices. The highest hole mobility of 0.13 cm{sup 2} V{sup -1} s{sup -1} is achieved in bottom gate and top-contact OTFT devices with on/off ratios in the range of 10{sup 6}-10{sup 7}. This work reveals that the replacement of thiophene by furan in DPP copolymers exhibits such a high mobility, which makes DPP furan a promising block for making a wide range of promising polymer semiconductors for broad applications in organic electronics.

Research Organization:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Sciences (CNMS)
Sponsoring Organization:
USDOE Office of Science (SC)
DOE Contract Number:
DE-AC05-00OR22725
OSTI ID:
1047635
Journal Information:
Journal of Materials Chemistry, Vol. 22, Issue 33; ISSN 0959-9428
Country of Publication:
United States
Language:
English