ChemComm
Page 4 of 4
Journal Name
COMMUNICATION
1
2
C. W. Tang and S. A. VanSlyke, Appl. Phys. Lett., 1987, 51, 913.
Lussem and K. Leo, Nature, 2009, 459, 234
(
a)
(b)
2
0
2
4
6
8
2
1
0
1
2
3
4
10
1.0 J = 1 mA/cm
1
6
10
.
DOI: 10.1039/C5CC00307E
2
3
4
10
3
4
5
6
7
C. Adachi, M. A. Baldo, M. E. Thompson and S. R. Forrest, J. Appl.
Phys., 2001, 90, 5048.
-
4
10
10
0.5
-
2
10
10
D. F. O’Brien, M. A. Baldo, M. E. Thompson and S. R. Forrest, Appl.
Phys. Lett., 1999, 74, 442.
-
0
10
10
12
0
.0
.8
0
4
8
400
500
600
H. Uoyama, K. Goushi, K. Shizu, H. Nomura and C. Adachi, Nature
012, 492, 234.
H. Tanaka, K. Shizu, H. Miyazaki and C. Adachi, Chem. Commun.
012, 48, 11392.
) Q. Zhang, J. Li, K. Shizu, S. Huang, S. Hirata, H. Miyazaki and C.
Adachi, J. Am. Chem. Soc., 2012, 134, 14706; ( ) S. Wu, M. Aonuma,
Q. Zhang, S. Huang, T. Nakagawa, K. Kuwabara and C. Adachi, J.
Mater. Chem C., 2014, , 421; ( ) Q. Zhang, B. Li, S. Huang, H.
Nomura, H. Tanaka and C. Adachi, Nat. Photon., 2014, , 326; ( ) S.
,
Voltage (V)
Wavelength (nm)
(
c)
(d)
2
0
1
3
2
4
,
1
0
0.6
1
2
1
0
.4
.2
2
3
4
(
a
0
b
0
1
0
0.0
-
2
-1
0
1
10
2
3
1
0
10
10
10
10
0.0 0.2 0.4 0.6
2
Current Density (mA/cm )
x
2
c
Fig. 5 (a) J‐V‐L characteristics, (b) normalized EL spectra, (c)
and (d) CIE coordinates for OLEDs using emitters
η
ext–J characteristics,
8
d
1‐4.
Y. Lee, T. Yasuda, Y. S. Yang, Q. Zhang and C. Adachi, Angew.
Chem. Int. Ed., 2014, 53, 6402.
of 19.5% and CIE of (0.16, 0.20) previously obtained for a
sulfone derivative.7c
8
M. J. Frisch, G. W. Trucks, H. B. Schlegel, G. E. Scuseria, M. A.
Robb, J. R. Cheeseman, G. Scalmani, V. Barone, B. Mennucci, G. A.
Petersson, H. Nakatsuji, M. Caricato, X. Li, H. P. Hratchian, A. F.
Izmaylov, J. Bloino, G. Zheng, J. L. Sonnenberg, M. Hada, M. Ehara,
K. Toyota, R. Fukuda, J. Hasegawa, M. Ishida, T. Nakajima, Y.
Honda, O. Kitao, H. Nakai, T. Vreven, J. A. Montgomery, Jr., J. E.
Peralta, F. Ogliaro, M. Bearpark, J. J. Heyd, E. Brothers, K. N. Kudin,
V. N. Staroverov, R. Kobayashi, J. Normand, K. Raghavachari, A.
Rendell, J. C. Burant, S. S. Iyengar, J. Tomasi, M. Cossi, N. Rega, J.
M. Millam, M. Klene, J. E. Knox, J. B. Cross, V. Bakken, C. Adamo,
J. Jaramillo, R. Gomperts, R. E. Stratmann, O. Yazyev, A. J. Austin,
R. Cammi, C. Pomelli, J. W. Ochterski, R. L. Martin, K. Morokuma,
V. G. Zakrzewski, G. A. Voth, P. Salvador, J. J. Dannenberg, S.
Dapprich, A. D. Daniels, Ö. Farkas, J. B. Foresman, J. V. Ortiz, J.
Cioslowski and D. J. Fox, Gaussian 09, Rev. A. 02, Gaussian, Inc,
Wallingford, CT, 2009.
However, we note that the peak EL wavelength of these
devices somewhat red-shifted compared that of their PL in
toluene solutions (Fig. 2(a)), which is mainly due to medium
effects from the host materials. With CIE coordinates of (0.15,
0
.09) and (0.15, 0.08) for the PL of emitters 3 and 4 in toluene,
even purer blue emission might be possible to obtain by further
optimizing the host materials and devices structures without
changing these materials, for example, by optimizing the
microcavity effect.15
The new emitters presented here prove the suitability of
1
0
H
-phenoxaborin as acceptor for wide-gap TADF materials,
and pure blue TADF with ext over 15% and CIE coordinates of
≤0.16, ≤0.16) was achieved for the first time using emitter
η
(
3
7
without any special optimization. These results demonstrate
the strong potential for TADF materials to be candidates for
solving the difficult challenge of obtaining pure, efficient, and
stable blue emission in OLEDs. Furthermore, using similar
bulky and twisted structures to prevent π-stacking between
emitters may be a route to reduce concentration quenching of
emission in films, enabling the optimization of carrier dynamics
in devices by varying the concentration of the emitter over a
9
(
a
) M. Melaïmi, S. Solé, C-W. Chiu, H. Wang and F. P. Gabbaï,
Inorg. Chem., 2006, 45, 8136; ( ) J. Kobayashi, T. Agou, and T.
Kawashima, Phosphorus, Sulfur, Silicon Relat. Elem., 2008, 183
89; (
Asian J., 2009,
) A. Schulz and W. Kaim, Chem. Ber., 1989, 122, 1863; (
Noda and Y. Shirota, J. Am. Chem. Soc., 1998, 120, 9714.
1 ( ) M. M. Rothmann, E. Fuchs, C. Schildknecht, N. Langer, C.
Lennartz, I. Münster and P. Strohriegl, Org. Electron., 2011, 12
192; ( ) P. Schrögel, N. Langer, C. Schildknecht, G. Wagenblast, C.
Lennartz and P. Strohriegl, Org. Electron., 2011, 12, 2047.
2 P. A. Vecchi, A. B. Padmaperuma, H. Qiao, L. S. Sapochak and P. E.
Burrows, Org. Lett., 2006, , 4211.
) Z. Tang and A Qin, “Aggregated induced emission”, Wiley 2013;
) Q. Wang, I. W. H. Oswald, X. Yang, G. Zhou, H. Jia, Q. Qiao, Y.
b
,
3
c
) J. Kobayashi, K. Kato, T. Agou and T. Kawashima, Chem.
, 42.
wide range while maintaining high
ext
η .
This research is supported by the Japan Society for the
4
Promotion of Science (JSPS) through its “Funding Program for 10 (
World-Leading Innovative R&D on Science and Technology
a
b
) T.
(
FIRST Program).”
Notes and references
1
a
,
a
Center for Organic Photonics and Electronics Research (OPERA),
1
b
Kyushu University, 744 Motooka, Nishi, Fukuoka 819-0395, Japan. E-
mail: yasuda@cstf.kyushu-u.ac.jp, adachi@cstf.kyushu-u.ac.jp
1
1
b
JST, ERATO, Adachi Molecular Exciton Engineering Project, c/o Center
8
for Organic Photonics and Electronics Research (OPERA), Kyushu
University, 744 Motooka, Nishi, Fukuoka 819-0395, Japan
3 (
(
a
b
c
INAMORI Frontier Research Center, Kyushu University, 744 Motooka,
Chen, J. Hoshikawa-Halbert and B. E. Gnade, Adv. Mat., 2014, 26
107.
,
Nishi, Fukuoka 819-0395, Japan
8
d
International Institute for Carbon Neutral Energy Research (WPI-I2CNER),
1
1
4 J. W. Sun, J. H. Lee, C. K. Moon, K. H. Kim, H. S. Shin and J. J.
Kyushu University, 744 Motooka, Nishi, Fukuoka 819-0395, Japan
Kim, Adv. Mater., 2014, 26, 5684.
†
Electronic Supplementary Information (ESI) available: Detailed
5 (
a
) N. Takada, T. Tsutsui and S. Saito, Appl. Phys. Lett., 1993, 63
032; ( ) A. Dodabalapur, L. J. Rothberg, T. M. Miller and E.W.
Kwock, Appl. Phys. Lett., 1994, 64, 2486.
,
experimental and synthetic procedures, material characterization, and
DFT calculations. See DOI: 10.1039/c000000x/
2
b
4
| J. Name., 2012, 00, 1‐3
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