Macroscopic Alignment of Poly(3-hexylthiophene) for Enhanced Long-Range Collection of Photogenerated Carriers

作者：Li Anton; Bilby David; Dong Ban Xuan; Amonoo Jojo; Kim Jinsang; Green Peter F

来源：Journal of Polymer Science Part B: Polymer Physics , 2016, 54(2): 180-188.

DOI：10.1002/polb.23888

• anisotropy
• charge transport
• conjugated polymers
• fibers
• morphology
• processing
• solar cells
• thin film transistors

An epitaxy-directing solvent additive 1,3,5-trichlorobenzene is combined with an off-center spin-casting technique to produce poly(3-hexylthiophene) (P3HT) fibers with uniaxial in-plane alignment on the centimeter scale. Photoconductive atomic force microscopy (pc-AFM) is used to characterize planar heterojunction devices assembled from phenyl-C-61 butyric acid methyl ester (PCBM) acceptor and both aligned and unaligned P3HT donor. By varying the relative positions of the laser spot (site of carrier generation) and probe (site of hole extraction), it is found that devices with aligned P3HT exhibit anisotropic and greatly enhanced long-range photocarrier transport, with nearly 10% of original photocurrent measured 400 mm from the laser spot along the direction parallel to the alignment. Complementary thin film transistor (TFT) measurements reveal a factor of similar to 3.5 difference in the hole mobilities parallel and perpendicular to the direction of alignment. Together, these findings highlight the importance of macroscopic alignment as a strategy to overcome the low mobilities of disordered polymer semiconductors.

• 出版日期2016-1-15