Annealing-Free High-Mobility Diketopyrrolopyrrole−Quaterthiophene Copolymer for Solution-Processed Organic Thin Film Transistors

• Published in: Journal of the American Chemical Society Vol. 133; no. 7; pp. 2198 - 2204
• Main Authors: Li, Yuning, Sonar, Prashant, Singh, Samarendra P, Soh, Mui Siang, van Meurs, Martin, Tan, Jozel
• Format: Journal Article
• Language: English
• Published: WASHINGTON American Chemical Society 23.02.2011; Amer Chemical Soc
• Subjects: Chemistry; Chemistry, Multidisciplinary; Physical Sciences; Science & Technology; SEMICONDUCTING POLYMERS; TRANSPORT; PERFORMANCE; MORPHOLOGY
• ISSN: 0002-7863; 1520-5126
• DOI: 10.1021/ja1085996

A donor−acceptor polymer semiconductor, PDQT, comprising diketopyrrolopyrrole (DPP) and β-unsubstituted quaterthiophene (QT) for organic thin film transistors (OTFTs) is reported. This polymer forms ordered layer-by-layer lamellar packing with an edge-on orientation in thin films even without thermal annealing. The strong intermolecular interactions arising from the fused aromatic DPP moiety and the DPP−QT donor−acceptor interaction facilitate the spontaneous self-assembly of the polymer chains into close proximity and form a large π−π overlap, which are favorable for intermolecular charge hopping. The well-interconnected crystalline grains form efficient intergranular charge transport pathways. The desirable chemical, electronic, and morphological structures of PDQT bring about high hole mobility of up to 0.97 cm2/(V·s) in OTFTs with polymer thin films annealed at a mild temperature of 100 °C and similarly high mobility of 0.89 cm2/(V·s) for polymer thin films even without thermal annealing.