Organic Letters
Letter
a
Table 2. EL Device Performance
Von (V)
λEL (nm)
ηc (cd/A)
ηc,max (cd/A)
ηp (lm/W)
ηext (%)
CIE (x,y)
I
2.8
3.0
2.7
2.8
479
426
491
474
0.92
0.58
2.68
0.99
1.07
0.85
2.68
1.22
0.69
0.34
2.55
0.69
0.48
0.63
1.06
0.70
0.23, 0.32
0.20, 0.17
0.26, 0.44
II
III
IV
0.18, 0.25
a
−2
−2
−2
Abbreviations: V , voltage required for 1 cd m ; η , current efficiency measured at 100 cd m ; η , power efficiency measured at 100 cd m ; η ,
on
c
p
ext
−2
measured at 100 cd m .
its photoluminescence data. Additionally, the electrolumines-
cence emission maxima of the devices based on 4a (I), 6a (III),
or 6b (IV) exhibited larger redshifts (53−72 nm) compared
with the corresponding photoluminescence data. These devices
exhibited lower turn-on voltages, less than 3.0 V, compared
dation of China (21574080), and the Shanghai Committee of
Science and Technology (15JC1490500).
REFERENCES
■
(1) (a) Anthony, J. E. Angew. Chem., Int. Ed. 2008, 47, 452.
(b) Anthony, J. E. Chem. Rev. 2006, 106, 5028.
4
b
with those of the anti-BN-heteroacene-based devices,
suggesting that the as-prepared syn-BN-heteroacenes could
(2) (a) Mei, J.; Diao, Y.; Appleton, A. L.; Fang, L.; Bao, Z. N. J. Am.
11
Chem. Soc. 2013, 135, 6724. (b) Chaskar, A.; Chen, H. F.; Wong, K. T.
Adv. Mater. 2011, 23, 3876.
offer favorable carrier transport for OLED devices. Device III
had a starting voltage of 2.7 V, ηc,max of 2.7, and external
quantum efficiency (EQE) of 1.06%, ranking it the most
(
3) (a) Jiang, W.; Li, Y.; Wang, Z. H. Chem. Soc. Rev. 2013, 42, 6113.
(b) Fukazawa, A.; Yamaguchi, S. Chem. - Asian J. 2009, 4, 1386.
4) (a) Hatakeyama, T.; Hashimoto, S.; Seki, S.; Nakamura, M. J. Am.
11
effective of the heteroacene-based blue OLED devices. These
results strongly support the hypothesis that molecular
symmetry enables efficient improvement of the fabrication
and performance of OLED devices.
(
Chem. Soc. 2011, 133, 18614. (b) Wang, X. Y.; Zhang, F.; Liu, J.; Tang,
R. Z.; Fu, Y. B.; Wu, D. Q.; Xu, Q.; Zhuang, X. D.; He, G. F.; Feng, X.
L. Org. Lett. 2013, 15, 5714. (c) Wang, X. Y.; Zhuang, F. D.; Wang, R.
B.; Wang, X. C.; Cao, X. Y.; Wang, J. Y.; Pei, J. J. Am. Chem. Soc. 2014,
136, 3764. (d) Hashimoto, S.; Ikuta, T.; Shiren, K.; Nakatsuka, S.; Ni,
J.; Nakamura, M.; Hatakeyama, T. Chem. Mater. 2014, 26, 6265.
In summary, we successfully designed and synthesized a new
family of angular BN-heteroacenes, featuring syn-structures that
provide them with unique molecular arrangements in the solid
state and significantly improved their photophysical properties
in comparison with their anti-isomers. These syn-BN-
heteroacenes were used as nondoped light-emitting host
materials to fabricate blue OLED devices that demonstrated
favorable performance including a low starting potential
without optimization. Our group is continuing to modify
these syn-BN-heteroacenes to improve their electronic proper-
ties to create high-performance blue OLED devices. Addition-
ally, the potential utilization of changes in molecular symmetry
to develop new types of promising organic materials is worthy
of further investigation.
(e) Wang, X. Y.; Zhuang, F. D.; Wang, X. C.; Cao, X. Y.; Wang, J. Y.;
Pei, J. Chem. Commun. 2015, 51, 4368. (f) Li, G.; Xiong, W. W.; Gu, P.
Y.; Cao, J.; Zhu, J.; Ganguly, R.; Li, Y. X.; Grimsdale, A. C.; Zhang, Q.
C. Org. Lett. 2015, 17, 560.
(5) (a) Xie, Z. Q.; Yang, B.; Li, F.; Cheng, G.; Liu, L. L.; Yang, G. D.;
Xu, H.; Ye, L.; Hanif, M.; Liu, S. Y.; Ma, D. G.; Ma, Y. G. J. Am. Chem.
Soc. 2005, 127, 14152. (b) Zhang, L.; Cao, Y.; Colella, N. S.; Liang, Y.;
Bredas, J. L.; Houk, K. N.; Briseno, A. L. Acc. Chem. Res. 2015, 48, 500.
(c) Xia, D.; Marszalek, T.; Li, M.; Guo, X.; Baumgarten, M.; Pisula,
W.; Mullen, K. Org. Lett. 2015, 17, 3074. (d) Shi, L.; Liu, Z.; Dong, G.;
̈
Duan, L.; Qiu, Y.; Jia, J.; Guo, W.; Zhao, D.; Cui, D.; Tao, X. Chem. -
Eur. J. 2012, 18, 8092. (e) Sahasithiwat, S.; Mophuang, T.;
Menbangpung, L.; Kamtonwong, S.; Sooksimuang, T. Synth. Met.
2
010, 160, 1148. (f) Pho, T. V.; Yuen, J. D.; Kurzman, J. A.; Smith, B.
G.; Miao, M.; Walker, W. T.; Seshadri, R.; Wudl. J. Am. Chem. Soc.
012, 134, 18185. (g) Okamoto, T.; Mitsui, C.; Yamagishi, M.;
ASSOCIATED CONTENT
Supporting Information
■
*
S
2
Nakahara, K.; Soeda, J.; Hirose, Y.; Miwa, K.; Sato, H.; Yamano, A.;
Matsushita, T.; Uemura, T.; Takeya, J. Adv. Mater. 2013, 25, 6392.
(
Tykwinski, R. R. Org. Lett. 2012, 14, 62. (b) Yanai, N.; Mori, T.;
Shinamura, S.; Osaka, I.; Takimiya, K. Org. Lett. 2014, 16, 240.
(c) Nakano, M.; Niimi, K.; Miyazaki, E.; Osaka, I.; Takimiya, K. J. Org.
Chem. 2012, 77, 8099.
6) (a) Lehnherr, D.; Hallani, R.; McDonald, R.; Anthony, J. E.;
Experimental details, NMR spectra, UV−vis spectra,
(
7) Liu, Y.; Shan, T.; Yao, L.; Bai, Q.; Guo, Y.; Li, J.; Han, X.; Li, W.;
Wang, Z.; Yang, B.; Lu, P.; Ma, Y. Org. Lett. 2015, 17, 6138.
8) (a) Bonifacio, M. C.; Robertson, C. R.; Jung, J.-Y.; King, B. T. J.
(
Org. Chem. 2005, 70, 8522. (b) Kar, G. K.; Haldar, M. K.; Gupta, S.;
Pan, D.; Ray, J. K. J. Indian. Chem. Soc. 1999, 76, 569.
AUTHOR INFORMATION
■
*
*
(9) (a) Bosdet, M. J. D.; Jaska, C. A.; Piers, W. E.; Sorensen, T. S.;
Parvez, M. Org. Lett. 2007, 9, 1395. (b) Jaska, C. A.; Emslie, D. J. H.;
Bosdet, M. J. D.; Piers, W. E.; Sorensen, T. S.; Parvez, M. J. Am. Chem.
Soc. 2006, 128, 10885.
Notes
(10) Cinar, M. E.; Ozturk, T. Chem. Rev. 2015, 115, 3036.
(11) Zhu, M. R.; Yang, C. L. Chem. Soc. Rev. 2013, 42, 4963.
The authors declare no competing financial interest.
ACKNOWLEDGMENTS
We are grateful for the financial supported from the National
Basic Research Program of China (973 Program:
■
2013CBA01602, 2012CB933404), the Natural Science Foun-
D
Org. Lett. XXXX, XXX, XXX−XXX