Regioregular Poly(3-pentylthiophene): Synthesis, Self-Assembly of Nanowires, High-Mobility Field-Effect Transistors, and Efficient Photovoltaic Cells

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• 作者：Pei-Tzu Wu ; Hao Xin ; Felix Sunjoo Kim ; Guoqiang Ren ; Samson A. Jenekhe
• 刊名：Macromolecules
• 出版年：2009
• 出版时间：November 24, 2009
• 年：2009
• 卷：42
• 期：22
• 页码：8817-8826
• 全文大小：1106K
• 年卷期：v.42,no.22(November 24, 2009)
• ISSN：1520-5835

文摘

We report the synthesis, characterization, solution-phase assembly of nanowires, field-effect charge transport, and photovoltaic properties of regioregular poly(3-pentylthiophene) (P3PT), the first regioregular poly(3-alkylthiophene) with an odd-numbered alkyl side chain length to be so investigated. Two samples of P3PT with weight-average molecular weights of 61800 and 77000 and 1.4−1.5 polydispersity index have comparable solubility and processability in organic solvents as regioregular poly(3-hexylthiophene) (P3HT) but have a higher melting transition at 259 °C. X-ray diffraction of P3PT films revealed a lamellar structure with an interlayer d₁₀₀ spacing of 1.51 nm and a π-stacking d₀₁₀ spacing of 0.374 nm, both smaller than in P3HT. Crystalline nanowires of 16−17 nm width and aspect ratios as high as 465 were assembled from P3PT solution. Field-effect transistors fabricated from P3PT thin films showed a mobility of holes of up to 0.10 cm²/(V s), and the carrier mobility increased with molecular weight. Bulk heterojunction solar cells based on P3PT/fullerene (PC₇₁BM) blend thin films had a power conversion efficiency of 3.70% under 100 mW/cm² AM1.5 solar illumination in air and a maximum external quantum efficiency of 69%. Similarly illuminated solar cells based on nanocomposites of P3PT nanowires/PC₇₁BM had a 3.33% power conversion efficiency. These results demonstrate that P3PT is an attractive polymer semiconductor suitable for applications in thin-film and nanowire-based field-effect transistors and bulk heterojunction solar cells.