Charged Carrier Mobility Study in Colh Mesophase
251
ophilic=fluorophobic interactions. Additionally, in the wide-angle region, two dif-
˚
˚
fused reflections come up at ca. 4.3 A and ca. 5.7 A corresponding to the liquid-like
order of the hydrocarbon aliphatic chains [17] and of the perfluoroalkyl chains [18–
20], respecting and the former is seen the C9OTP indicating the molecular stacking
of core parts in column is rather disordered. Considering the result of XRD measure-
ments, the thermal stability of Colhd mesophase was stabilized by fluorophilic=fluor-
fluorophobic interactions which induce a nano-segregated structure in a column. On
the other hand, the mobility behavior in the Colhd mesophases is common in both
F6=C9 and C9OTP and this is reasonably suggested by the carrier mobility values
is the same order.
4. Conclusion
The carrier mobility in the Colhd mesophase of a perfluoroalkylated triphenylene
derivative (F6=C9) was evaluated by TOF measurements. F6=C9 shows an ambipo-
lar character and, the positive and negative carriers are in the order of 10ꢀ4 cm2
V
ꢀ1sꢀ1. Also for the negative carriers, the slow component could be observed in
the decay curves corresponding to the mobility in the order of 10ꢀ5 cm2Vꢀ1sꢀ1, prob-
ably due to the ionic transport. The carrier mobility is independent of the applied
field ranging from 10 kV=cm to 40 kV=cm. These carrier transport properties are
almost identical to those of the corresponding hydrocarbon homologues (C9OTP).
XRD measurements indicate that the mesophase formed by F6=C9 is a hexag-
onal disordered columnar (Colhd) mesophase, and it is almost comparable to that
of C9OTP. Though the fluorophilic=fluorophobic interactions among the peripheral
chains stabilize the columnar structure, the stacking of triphenylene core along the
columnar axis in F6=C9 is a disordered state which is just the same situation on
C9OTP. It is reasonable to think that the observed carrier mobility of F6=C9 is in
the comparable order to that of C9OTP.
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