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

Abstract

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 μm and a length of hundreds of μm 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 cm2/Vs was obtained.

Alignment and Photopolymerization of Hexa-peri-hexabenzocoronene Derivatives Carrying Diacetylenic Side Chains for Charge-Transporting Application

“…As shown in Figure c, obvious stretching bands at 1500 and 2110 cm –1 , assignable to the double bond and triple bond in the poly­(ene–yne) backbones, were observed, clear evidence that extended poly­(ene–yne) chains were formed . Stronger Raman signals were obtained when the polarization was parallel to the coating direction, which indicates that the polymerization direction was parallel to the coating direction. , It is noted that no peak was observed for the film of monomeric 4 . A previous report suggested that a strong fluorescence of the HBC-DA film may overwhelm the Raman spectra .…”

“…36 the polarization was parallel to the coating direction, which indicates that the polymerization direction was parallel to the coating direction. 7,31 It is noted that no peak was observed for the film of monomeric 4. A previous report suggested that a strong fluorescence of the HBC-DA film may overwhelm the Raman spectra.…”

“…Micrometer-sized single crystals of poly­(pentacosa-10,12-diynoic acid) were shown experimentally to give a high mobility of up to 50 cm 2 V –1 s –1 . However, attempts to align 1,6-di-( N -carbazolyl)-2,4-hexadiyne (DCHD) molecules into oriented thin films on the substrate only gave very poor field-effect mobility after photopolymerization, presumably because some distance mismatches before and after polymerization resulted in numerous defects within the film so that the charge transport is hampered . To date, the structure correlation between diacetylenic molecules and polymerized thin film and thus transistor performance is not clear.…”