Aligning poly[1,6-di-(N-carbazolyl)-2,4-hexadiyne] crystalline fibers as conducting channels for transistor applications

Aligned crystallites of 1,6-di-(N-carbazolyl)-2,4-hexadiyne (DCHD) were prepared on the phenyltrichlorosilane-modified SiO2/Si surface using the brush-coating method. The length and width as well as the orientation of the crystallites depend on the coating speed. At a lower coating speed of 0.2 ~ 0.3 mm/s, well-separated fibers with a width of 1-2 mu m and a length of hundreds of mu m were grown along the coating direction. Higher speeds resulted in shorter fibers together with randomly oriented tiny crystallites appearing in between. The diacetylene crystallites upon UV irradiation gave polydiacetylene fibers with deformations along the fiber axis. The poly(ene-yne) backbones were shown to align along the fiber axes. With these poly-DCHD fibers as a conducting channel for transistor fabrication, a highest field-effect mobility of 0.039 cm(2)/Vs was obtained.