Dibenzothiopheno[6,5-b:6′,5′-f]thieno[3,2-b]thiophene (DBTTT): High-Performance Small-Molecule Organic Semiconductor for Field-Effect Transistors

Article abstract of DOI:10.1021/jacs.5b01108

We present the synthesis, characterization, and structural analysis of a thiophene-rich heteroacene, dibenzothiopheno[6,5-b:6′,5′-f]thieno[3,2-b]thiophene (DBTTT) as well as its application in field-effect transistors. The design of DBTTT is based on the enhancement of intermolecular charge transfer through strong S-S interactions. Crystal structure analysis showed that the intermolecular π-π distance is shortened and that the packing density is higher than those of the electronically equivalent benzene analogue, dinaphtho-[2,3-b:2′,3′-f]thieno[3,2-b]thiophene (DNTT). The highest hole mobility we obtained in polycrystalline DBTTT thin-film transistors was 19.3 cm²·V^-1·s^-1, six times higher than that of DNTT-based transistors. The observed isotropic angular mobilities and thermal stabilities at temperatures up to 140 °C indicate the great potential of DBTTT for attaining device uniformity and processability.

Full text of DOI:10.1021/jacs.5b01108

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Communication
Dibenzothiopheno[6,5-b:6’,5’-f]thieno[3,2-b]thiophene
(DBTTT): High-Performance Small-Molecule
Organic Semiconductor for Field-Effect Transistors
Jeong-Il Park, Jong Won Chung, Joo-Young Kim, Jiyoul Lee, Ji Young Jung,
Bonwon Koo, Bang-Lin Lee, Soon W. Lee, Yong Wan Jin, and Sang Yoon Lee
J. Am. Chem. Soc., Just Accepted Manuscript • DOI: 10.1021/jacs.5b01108 • Publication Date (Web): 31 Mar 2015
Downloaded from http://pubs.acs.org on April 7, 2015
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Dibenzothiopheno[6,5-b:6′,5′-f]thieno[3,2-b]thiophene
(DBTTT): High-Performance Small-Molecule Organic Semi-
conductor for Field-Effect Transistors
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JeongꢀIl Park,1*‡, Jong Won Chung,1‡ JooꢀYoung Kim,1 Jiyoul Lee,1,3 Ji Young Jung,1 Bonwon Koo,1
BangꢀLin Lee,1 Soon W. Lee,2 Yong Wan Jin,1 and Sang Yoon Lee1
1Material Research Center, Samsung Advanced Institute of Technology, Samsung Electronics Co., Ltd., Samsungꢀro 130,
Yongtongꢀgu, Suwonꢀsi, Gyeonggiꢀdo 443ꢀ803, Korea
2Department of Chemistry, Sungkyunkwan University Natural Science Campus, Seobuꢀro 2066, Janganꢀgu, Suwonꢀsi,
Gyeonggiꢀdo 440ꢀ746, Korea
3Department of Graphic Arts Information Engineering, College of Engineering, 365 Sinseronꢀro, Namꢀgu, Busan 608ꢀ739, Korea
KEYWORDS: Organic semiconductor, organic fieldꢀeffect transistor, organic thinꢀfilm transistor
Supporting Information Placeholder
stead of naphthalene to facilitate the charge transfer between
molecules by increasing the π–π orbital overlap; however, the
resulting TFT performance did not surpass that of TFTs based
on unmodified DNTT. While there are some examples of the
ABSTRACT: We present the synthesis, characterization, and
structural analysis of a thiopheneꢀrich heteroacene, dibenꢀ
zothiopheno[6,5ꢀb:6',5'ꢀf]thieno[3,2ꢀb]thiophene (DBTTT), as
well as its application in fieldꢀeffect transistors. The design of
mobility being enhanced by sideꢀchain modifications of
DBTTT is based on the enhancement of intermolecular charge
DNTT,15–20 we focused on developing new core molecules
transfer through strong S–S interactions. Crystal structure
with high performance. Although theoretical simulations sugꢀ
analysis showed that the intermolecular π–π distance is shortꢀ
gest that the highly symmetric benzene ring is more favorable
ened and the packing density is higher than those of the elecꢀ
tronically equivalent benzene analog, dinaphthoꢀ[2,3ꢀb:2′,3′ꢀ
f]thieno[3,2ꢀb]thiophene (DNTT). The highest hole mobility
we obtained in polycrystalline DBTTT thinꢀfilm transistors
than the thiophene ring for low reorganization energy, and
charge transfer is dependent on the conjugation length of the
molecule, we focused on the compactness of molecules for a
was 19.3 cm2·V‒1·s‒1, six times higher than that of DNTTꢀ
higher density of chargeꢀcarrying species and introducing
strong S–S and S–C interactions between thiophenes instead
based transistors. The observed isotropic angular mobilities
and thermal stabilities at temperatures up to 140°C indicate the
of the C–Hꢀꢀπ interactions through benzene rings.
great potential of DBTTT for attaining device uniformity and
processability.
DNTT
DBTTT
Organic semiconductors are drawing attention as promising
materials that can be applied in flexible electronics, despite
their relatively low charge mobility when compared to their
inorganic counterparts.1,2 New materials with high mobilities
above 10 cm2·V‒1·s‒1 and recently developed sophisticated
solutionꢀprocessing techniques for singleꢀcrystalline devices
have spurred many researchers to develop organic semiconꢀ
Figure 1. Chemical structure of DBTTT and DNTT.
By replacing the terminal benzene rings of DNTT with two
thiophene rings, as shown in Figure 1, we propose a fourꢀ
thiopheneꢀfused heteroacene, dibenzothiopheno[6,5ꢀb:6',5'ꢀ
f]thieno[3,2ꢀb]thiophene (DBTTT), as a candidate for a highꢀ
erꢀchargeꢀtransporting material. Owing to the higher number
of thiophenes, DBTTT has a lower HOMO level and a larger
HOMO–LUMO energy gap than DNTT in molecular orbital
calculation (HOMO: highest occupied molecular orbital;
LUMO: lowest unoccupied molecular orbital). Calculations
show that the reorganization energy of DBTTT (146 meV) is
comparable to that of DNTT (128 meV). In addition, crystalꢀ
structure prediction using the Polymorph package in Material
Studio (BIOVIA, formerly Accelrys, USA) shows that comꢀ
pared to DNTT, DBTTT molecules are more closely packed
and the packing density is over 10% higher (see Supporting
information). We report here its synthesis, physicochemical
3 6
–
ductors for nextꢀgeneration flexible electronics.
Heteroacenes that contain chalcogenophene have been acꢀ
tively investigated as semiꢀconducting materials because they
are more stable in air than acenes and various chemical modiꢀ
fications of the compounds are possible.7,8 While there have
been many attempts to combine benzene with thiophene rings
to produce higherꢀperformance materials, only a few derivaꢀ
tives are known to show high mobilities above 1 cm2·V‒1·s‒1.
Diaceneꢀfused thienoꢀ[3,2ꢀb]thiophenes (DNTTs),9 have been
studied in depth by many researchers to demonstrate their
applicability in newꢀconcept devices because of their high
mobility.10–12 For further enhancement of the mobility of
DNTT, Takimiya13 and Bao14 et al. introduced anthracene inꢀ
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properties, crystal structure, and thinꢀfilm and singleꢀ
crystalline transistor characteristics to examine the suitability
of DBTTT as a highꢀperformance semiconducting material.
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In our study, DBTTT was regiospecifically synthesized by
adapting Neckers’ method,21 where diꢀlithiated thieno[3,2ꢀ
b]thiophene was condensed with 3ꢀbromoꢀthiopheneꢀ2ꢀ
carboxaldehyde and by in situ dehydroxylation using sodium
cyanoborohydride to afford compound 3 in Scheme 1. Using a
little excess of tertꢀbutyllithium (tꢀBuLi) and dimethylformaꢀ
mide (DMF), the dibromo compound was converted to dicarꢀ
boxaldehyde, compound 4, with good yield (42% in three
steps). The tandem intramolecular cyclodehydration (heteroꢀ
Bradsher reaction) afforded the final product as an offꢀwhite
solid, which was further purified by sublimation.
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Scheme 1. Synthetic route to DBTTT
Figure 2. Crystal structure and transfer integral value of DBTTT.
ZnI 2, NaBH 3CN
(a, b) There are two kinds of intermolecular S···S contacts (S1–
S4, S2–S3) that are shorter than the sum of van der Waals radius
of the sulfur atoms (3.70 Å). (c) cꢀaxis projection representing the
herringbone structure. The transfer integrals were computed for
the transverse (VT1 and VT2) and parallel (VTP) components of
pairs of nearest neighbors. H atoms have been omitted for clarity.
(d) Comparison of transfer integral values of DBTTT with those
of other thienothiopheneꢀcored organic semiconductors, DNTT
and DATT.
n-BuLi, ether
oC to RT, overnight
DCM, RT, overnight
0
1
2
3
n-BuLi, DMF
ether, THF
Amberlyst 15
benzene, Dean Stark
−
4
DBTTT
DBTTT is a thermally stable paleꢀyellow crystal that subꢀ
limes at temperatures above 350°C (Tm = 427°C). The optical
HOMO–LUMO gap estimated from the absorption edge (λedge
= 423 nm) is about 2.9 eV, which is similar to that of DNTT
(3.0 eV). The ionization potential for DBTTT is 5.32 eV beꢀ
low the vacuum level. Judging from this data, we expect
DBTTT to be electrochemically as stable as DNTT.
Thinꢀfilm transistors were fabricated by vacuum deposition
on the octadecyltrichlorosilane (ODTS)ꢀtreated SiO2/Si (300ꢀ
nmꢀthick thermal SiO2 on Si wafer) substrates. The channel
width and length of the DBTTT were 1,000 and 100 μm, reꢀ
spectively. Table 1 summarizes the performance of the
DBTTTꢀbased organic field fieldꢀeffect transistors (OFETs)
prepared at various substrate temperatures (Tsub). All the deꢀ
vices showed typical pꢀchannel fieldꢀeffect transistor (FET)
characteristics. In particular, excellent FET characteristics,
with average mobility of ꢁFET = 13.9 ± 2.3 cm2·V‒1·s‒1 and
on/off current ratio of Ion/Ioff > 107 were obtained from 36 deꢀ
vices fabricated at Tsub = 60°C. Among the results, the highest
hole mobility of 19.3 cm2·V‒1·s‒1 was achieved with a threshꢀ
old voltage (Vth) of ‒11.2 V in the saturation region. The value
of Ion/Ioff was around 3.6 × 108. The mobility is the highest
value ever reported among polycrystalline thinꢀfilm transistors
fabricated on SiO2/Si substrates. The output characteristics
(drain current, ID, versus drain–source bias, VDS) and transfer
characteristics (ID versus gate–source bias, VGS) of the devices
are shown in Figure 3.
Singleꢀcrystal Xꢀray analysis of DBTTT elucidated that the
compound exhibited a typical herringbone packing structure
with a small standard deviation of 0.04 Ǻ. Compared to the
wellꢀknown DNTT, the intermolecular distance between two
adjacent DBTTT molecules along the πꢀstacking direction was
dramatically reduced to 5.91 Ǻ (6.19 Ǻ for DNTT), and all
sulfur atoms participated in the sulfur–sulfur van der Waals
interaction on the a–b plane and even along the cꢀaxis. Unlike
other highꢀperformance semiconducting materials like DNTT,
pentacene, or rubrene, the transfer integral values22 of DBTTT
on the a–b plane were quite well balanced (VT1 = 67, VT2 = 50,
and VTP = 70 meV). The Marcusꢀtheoryꢀbased23 directional
charge mobilities of DBTTT ranged from 2.5 to 5.6 cm2·V‒1·s‒
1. Compared to the structurally similar DNTT and dianꢀ
thra[2,3ꢀb:2',3'ꢀf]thieno[3,2ꢀb]thiophene (DATT) crystals, the
transfer integral values were quite distinguishable (Figure 2d),
and the calculated ratio between the maximum and minimum
angular mobility, ꢁmax/ꢁmin, of DBTTT was much lower than
those of DNTT and DATT (9.3/2.9 and 15.5/5.2, respectively).
It is noteworthy that even though the maximum and average
mobilities of DBTTT are expected to be lower, the isotropic
mobility of DBTTT can be evaluated in polycrystalline thin
films because anisotropic charge transport may obstruct the
prediction of the characteristics and complicate circuit and
device design. Furthermore, the grain boundary of isotropic
microcrystals probably reduces the energy barrier to transport
and possibly contribute to the improvement in device uniꢀ
formity.
Table 1. Experimental characteristics of DBTTTꢀbased
organic fieldꢀeffect transistors (OFETs)
Mobilitya
[cm2·V–1·s–1]
Threshold
Substrate
temp. [°C]
Ion/Ioff
voltage [V]
RT
40
60
80
2.82 ± 0.71
6.89 ± 0.84
13.87 ± 2.34
8.26 ± 1.15
106‒107
107
108
‒ 7.91 ± 2.34
‒ 8.32 ± 1.14
‒ 9.82 ± 2.75
‒ 9.76 ± 0.75
107
aExtracted from saturation regime (VDS = –40 V)
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60°C; blue line: Tsub = 80°C). The dꢀspacing of the evaporated
DBTTT film, obtained from the reflection peak, was 15.5 Å.
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Figure 3. Device performance of DBTTTꢀbased OFETs. (a) Outꢀ
put characteristics (ID versus VDS) and (b) transfer characteristics
(ID versus VGS) of DBTTTꢀbased OFETs fabricated on ODTSꢀ
treated SiO2/Si substrate with a width/length ratio of 10. (c) Hisꢀ
togram of the mobilities obtained from 36 devices. The inset imꢀ
age shows the device structure with top contact and bottom gate.
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Figure 5. Highly regular hexagonal crystal and electrical characꢀ
teristics of singleꢀcrystalline FETs along different crystal planes.
(a) Optical microscope image of the hexagonal crystal with the
facets indexed. (b) Herringbone arrangement of the molecules
when viewed along the cꢀaxis. (c) Optical microscope image of
DBTTT transistors consisting of individual single crystals with
different channel directions. Carrier transport along the (left)
[100], (center) [110], and (right) [010] directions. (d) Experiꢀ
mental results of the channelꢀdirectionꢀdependent chargeꢀcarrier
mobility in the range of 0–180° (VGS = ‒40 V; VDS = ‒10 V, ‒20
V).
The substrate temperature influenced the crystalline doꢀ
main sizes, as shown in the atomic force microscopy (AFM)
images (Figure 4a). The grains were ~0.1
thin films deposited at room temperature (RT), whereas the
grain sizes were 1–2 m at in the films deposited at Tsub
μm in size in the
μ
=
60°C. Apparently, the larger grains contributed to the enꢀ
hancement in hole mobility.24 When DBTTT was deposited at
a higher temperature (80°C), larger, albeit nonꢀcontinuous,
crystallites were observed, which is consistent with the weaker
fieldꢀeffect response in actual devices.
To confirm the intrinsic mobility of DBTTT, singleꢀ
crystalline fieldꢀeffect transistors (SCꢀFETs) were fabricated.
Using the physical vapor transport (PVT) method,25 the crysꢀ
tals were directly grown on a SiO2/Si substrate coated with a
selfꢀassembled monolayer (SAM) of ODTS. The micrometerꢀ
The Xꢀray diffraction (XRD) patterns of the DBTTT thin
films show wellꢀdefined crystalline character and the peaks are
clearly assignable to (001) reflections (Figure 4c). A primary
diffraction peak appears at 2θ = 5.68°, with thirdꢀ to sixthꢀ
order diffraction peaks at 2θ = 17.10, 22.86, 28.66, and 34.58°,
respectively. The strong intensity of the XRD peaks indicates
the formation of lamellar ordering and the crystallinity of the
substrate. The dꢀspacing of DBTTT obtained from the first
reflection peak was 15.5 Å, which is consistent with the sinꢀ
gleꢀlayer thickness obtained by AFM (Figure 4b). As shown in
the AFM images (Figure 4a and 4b), the molecules stood alꢀ
most perpendicular to the substrate surface and the packing
nature of the microcrystal in the thin film was similar to that of
the solutionꢀgrown single crystal.
sized singleꢀcrystalline plates, as large as 20 × 20 ± 5 μm with
a typical thickness of ~ 40 ± 2 nm, were obtained with a reguꢀ
lar hexagonal shape, where the angles of the facets match
those calculated from the Xꢀray structure (Figure 2a and 2b).
The SCꢀFETs were fabricated using the “organic ribbon mask”
technique,26 in which an individual organic ribbon was used as
a mask for the deposition of gold for the source and drain elecꢀ
trodes. Topꢀcontact bottomꢀgate devices were produced (Figꢀ
ure 5c). The angular dependence of the fieldꢀeffect mobility of
DBTTT appeared quite uniform, regardless of the channel
direction. As shown in Figure 5d, the transistors exhibited
very similar mobilities of about 4.06–5.11 cm2·V‒1·s‒1 along
the [100], [110], and [010] directions. As the gate bias inꢀ
creased, the saturation mobility increased to 8.53 ± 0.56
cm2·V‒1·s‒1 (VDS at ‒20 V). With further increase of the bias to
‒40 V, some devices underwent breakage, although the saturaꢀ
tion mobility was observed to be 18.0 cm2·V‒1·s‒1.
In order to evaluate the thermal stability of DBTTTꢀbased
FET devices, the temperatureꢀdependent electrical characterisꢀ
tics were measured by elevating the temperature from RT to
200°C in steps of 10°C. The transfer characteristics, mobility,
and Vth remained at their initial values until the temperature
reached 140°C (Figure 6). Although a 50% decrease in mobiliꢀ
ty and negative shift of Vth were observed when the temperaꢀ
ture exceeded 150°C, the mobility was restored to the initial
value after cooling to RT. Compared to its benzene analog,
DNTT, the improved thermal stability of DBTTT can be exꢀ
plained by the stiffness of the packing structure of DBTTT
owing to multiple S···S contacts and closer π–π distance, reꢀ
sulting in higher packing density (1.473 g·cm–3 for DNTT,
1.622 g·cm–3 for DBTTT).
Figure 4. AFM image and XRD patterns obtained at different
substrate temperatures. (a) AFM images of the evaporated thin
films deposited on ODTSꢀtreated SiO2/Si substrates at Tsub of (1)
25, (2) 40, (3) 60, and (4) 80°C. Scale bar: 1 ꢁm. (b) Crossꢀ
sectional profile of (a3). (c) Outꢀofꢀplane XRD patterns of
DBTTT on ODTSꢀmodified substrates at different substrate temꢀ
peratures (black line: simulated from single crystallographic data;
red line: Tsub = 25°C; green line: Tsub = 40°C; orange line: Tsub
=
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(1) Gelinck, G.; Heremans, P.; Nomoto, K.; Anthopoulos, T. D.
Adv. Mater. 2010, 22, 3778.
(2) Di, C.; Zhang, F.; Zhu, D. Adv. Mater. 2013, 25, 313.
1
2
3
4
5
6
7
8
(3) Minemawari, H.; Yamada, T.; Matsui, H.; Tsutsumi, J.; Haas,
S.; Chiba, R.; Kumai, R.; Hasegawa, T. Nature 2011, 475, 364.
(4) Giri, G.; Verploegen, E.; Mannsfeld, S.; AtahanꢀEvrenk, S.;
Kim, D. H.; Lee, S. Y.; Becerril, H. A.; AspuruꢀGuzik, A.; Toney, M.
F.; Bao, Z. Nature 2011, 480, 504.
(5) Yuan, Y.; Giri, G.; Ayzner, A. L.; Zoombelt, A. P.; Mannsfeld,
C. B.; Chen, J.; Nordlund, D.; Toney, M. F.; Huang, J.; Bao, Z. Nat.
Commun. 2014, 5, 3005.
(6) Mitsui, C.; Okamoto, T.; Yamagishi, M.; Tsurumi, J.; Yoꢀ
shimoto, K.; Nakahara, K.; Soeda, J.; Hirose, Y.; Sato, H.; Yamano,
A.; Uemura, T.; Takeya, J. Adv. Mater. 2014, 26, 4546.
(7) Takimiya, K.; Shinamura, S.; Osaka, I.; Miyazaki, E. Adv. Maꢀ
ter. 2011, 23, 4347.
9
10
11
12
13
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15
16
17
18
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20
21
22
23
24
25
26
27
28
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39
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53
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55
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59
60
Figure 6. (a) Transfer curves and (b) mobility and Vth of DBTTT
at different temperatures.
(8) Takimiya, K.; Osaka, I.; Mori, T.; Nakano, M. Acc. Chem. Res.
2014, 47, 1493.
(9) Yamamoto, T.; Takimiya, K. J. Am. Chem. Soc. 2007, 129,
2224.
We have designed and efficiently synthesized a novel orꢀ
ganic semiconductor with thermal stability and durability. The
highꢀperformance transistor characteristics originated from the
unique interaction between DBTTT molecules owing to the
additional thiophenes, resulting in closer contact in the crystal
lattice. In addition to the strong π–π stacking interaction, the
intermolecular networking in the crystal lattice through S···S
van der Waals contacts dramatically enhanced the chargeꢀ
carrying mobility to 19.3 cm2·V‒1·s‒1 in a polycrystalline thinꢀ
film transistor. The isotropic chargeꢀtransfer characteristics of
singleꢀcrystalline FETs are considered an additional benefit
for facilitating charge transfer in multigrain thin films.27,28
Based on these results, we conclude that DBTTT can be a very
promising candidate for practical application in future organic
electronics.
(10) Zschieschang, U.; Ante, F.; Kalblein, D.; Yamamoto, T.;
Takimiya, K.; Kuwabara, H.; Ikeda, M.; Sekitani, T.; Someya, T.;
BlochwitzꢀNimoth, J.; Klauk, H. Org. Electron. 2011, 12, 1370ꢀ1375.
(11) Kuribara, K.; Wang, H.; Uchiyama, N.; Fukuda, K.; Yokota,
T.; Zschieschang, U.; Jaye, C.; Fischer, D.; Klauk, H.; Yamamoto, T.;
Takimiya, K.; Ikeda, M.; Kuwabara, H.; Sekitani, T.; Loo, Y.ꢀL.;
Someya, T. Nat. Commun. 2012, 3, 723.
(12) Ante, F.; Kalblein, D.; Zschieschang, U.; Canzler, T. W.;
Werner, A.; Takimiya, K.; Ikeda, M.; Sekitani, T.; Someya, T.; Klauk,
H. Small 2011, 7, 1186.
(13) Niimi, K.; Shinamura, S.; Osaka, I.; Miyazaki, E.; Takimiya,
K. J. Am. Chem. Soc. 2011, 133, 8732.
(14) Sokolov, A. N.; AtahanꢀEvrenk, S.; Mondal, R.; Akkerman, H.
B.; SanchezꢀCarrera, R. S.; GranadosꢀFocil, S.; Schrier, J.; Mannsfeld,
C. B.; Zoombelt, A. P.; Bao, Z.; AspuruꢀGuzik, A. Nat. Commun.
2011, 2, 437.
(15) Kang, M. J.; Doi, I.; Mori, H.; Miyazaki, E.; Takimiya, K.;
Ikeda, M.; Kuwabara, H. Adv. Mater. 2011, 23, 1222.
(16) Niimi, K.; Kang, M. J.; Miyazaki, E.; Osaka, I.; Takimiya, K.
Org. Lett. 2011, 13, 3430.
(17) Hofmockel, R.; Zschieschang, U.; Kraft, U.; Rȍdel, R.; Hanꢀ
sen, N. H.; Stolte, M.; Wűrthner, F.; Takimiya, K.; Kern, K.; Pflaum,
J.; Klauk, H. Org. Electron. 2013, 14, 3213.
(18) Matsumoto, T.; OuꢀYang, W.; Miyake, K.; Uemura, T.;
Takeya, J. Org. Electron. 2013, 14, 2590.
(19) Yokota, T.; Kuribara, K.; Tokuhara, T.; Zschieschang, U.;
Klauk, H.; Takimiya, K.; Sadamitsu, Y.; Hamada, M.; Sekitani, T.;
Someya, T. Adv. Mater. 2013, 25, 3639.
(20) Amin, A. Y.; Khassanov, A.; Reuter, K.; MeyerꢀFriedrichsen,
T.; Halik, M. J. Am. Chem. Soc. 2012, 134, 16548.
(21) Wex, B.; Kaafarani, B. R.; Kirschbaum, K.; Neckers, D. C. J.
Org. Chem. 2005, 70, 4502.
(22) ADF2008.01; SCM, Theoretical Chemistry, Vrije Universiteit:
Amsterdam, The Netherlands; http://www.scm.com (last accessed
date is Oct. 14, 2014)
(23) Marcus, R. A. Angew. Chem. Int. Ed. Engl. 1993, 32, 1111.
(24) Headrick, R. L.; Wo, S.; Sansoz, F.; Anthony, J. E. Appl. Phys.
Lett. 2008, 92, 063302.
(25) Laudise, R. A.; Kloc, Ch.; Simpkins, P. G.; Siegrist, T. J.
Cryst. Growth 1998, 187, 449.
(26) Jiang, L; Gao, J.; Wang, E.; Li, H.; Wang, Z.; Hu, W.; Jiang, L.
Adv. Mater. 2008, 20, 2735.
(27) Reese, C.; Roberts, M. E.; Parkin, S. R.; Bao, Z. Appl. Phys.
Lett. 2009, 94, 202101.
(28) Lee, S. S.; Loth, M. A.; Anthony, J.; Loo, Y.ꢀL. J. Am. Chem.
Soc. 2012, 134, 5436.
ASSOCIATED CONTENT
Supporting Information.
Experimental details, synthesis, characterization, device fabricaꢀ
tion, theoretical studies, and crystal data. This material is availaꢀ
ble free of charge via the Internet at http://pubs.acs.org.
AUTHOR INFORMATION
Corresponding Author
*Jeong.park@samsung.com
Author Contributions
‡J.P. and J.W.C. contributed equally to the manuscript. All authors
revised and approved the manuscript.
Notes
The authors declare no competing financial interest.
ACKNOWLEDGMENT
The authors gratefully acknowledge W. Hu (ICCAS) for supportꢀ
ing the fabrication of SCꢀFET devices, K.E. Lee (SKKU) for her
assistance with the work on Xꢀray single crystallography, A. Asꢀ
puruꢀGuzik (Harvard University) for providing DATT crystal
structure files, and Z. Bao (Stanford University) for useful discusꢀ
sions. This work was supported in part by the Global Leading
Technology Program funded by the Ministry of Trade, Industry
and Energy, Republic of Korea. (10042419).
REFERENCES
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