Nature - USA (2019-07-18)

reSeArCH Letter

a

70 nm 20 nm

0.34 nm

0.53 nm ii

0.50 nm

0.38 nm

i

3.0 nm

i

ii

1 nm 1 nm 0.43 nm

b

cd

e f

g

Extended Data Fig. 9 | STM and AFM images of armchair-type GNR 8.
a, S TM image of armchair-type GNR 8 (Mn = 2.4 ×  104  Da, Đ = 1.32)
deposited on HOPG (U = 1.0 V, I =  250  pA, T =  78  K). b, Dimeric
assembly model of GNR 8. c, d, Cross-sectional height profile taken
perpendicularly (i) and horizontally (ii) with respect to the wire shown
in a. The observed substance had about 0.4 nm thickness and 3  nm
width, and the repeating peripheral stripes had 0.4–0.5 nm intervals ((i)
and (ii)). The existence of this substance was considered as the assembly
of two molecules of 8 , as depicted in b, and the observed periodicity of
0.4–0.5 nm corresponds to the longitudinal length between the alkyl
side chains ((ii) in d). e, AFM phase image of self-assembling GNR 8
(Mn = 2.4 ×  104  Da, Đ = 1.32) on graphene cleaved on SiO 2. f, Magnified
AFM phase image of e. g, Cross-sectional height profile taken along the
white line in f, perpendicularly to the observed stripe.