Comparative studies on inorganic and organic electron acceptors used as p-dopants in N,N′-di(naphthalene-1-yl)-N,N′-diphenyl-benzidine (NPB) in organic light-emitting diodes (OLEDs) are carried out. It demonstrates that 1,4,5,8,9,11-hexaazatriphenylene-hexacarbonitrile (HAT-CN) doped hole-injecting layer is superior to molybdenum trioxide (MoO3) doped one in device efficiency and stability. Combining with absorption spectral measurement, the effectiveness of a p-doped NPB in OLEDs does not solely rely on the generation of charge-transfer complexes in the doped NPB. The detailed difference between MoO3 and HAT-CN as p-dopants in NPB is further investigated by evaluating the hole injection efficiency, hole barrier height, and surface morphology of the doped films.
REFERENCES
1.
M. G.
Helander
, Z. B.
Wang
, J.
Qiu
, M. T.
Greiner
, D. P.
Puzzo
, Z. W.
Liu
, and Z. H.
Lu
, Science
332
, 944
(2011
).2.
J.
Kido
and T.
Matsumoto
, Appl. Phys. Lett.
73
, 2866
(1998
).3.
D. Y.
Zhou
, S. D.
Cai
, W.
Gu
, L. S.
Liao
, and S. T.
Lee
, Appl. Phys. Lett.
97
, 223302
(2010
).4.
Z.
Wang
, Y.
Lou
, S.
Naka
, and H.
Okada
, Appl. Phys. Lett.
98
, 063302
(2011
).5.
H.
Lee
, S. W.
Cho
, K.
Han
, P. E.
Jeon
, C. N.
Whang
, K.
Jeong
, K.
Cho
, and Y.
Yi
, Appl. Phys. Lett.
93
, 043308
(2008
).6.
C. H.
Gao
, S. D.
Cai
, W.
Gu
, D. Y.
Zhou
, Z. K.
Wang
, and L. S.
Liao
, ACS Appl. Mater. Interfaces
4
, 5211
(2012
).7.
C.
Ganzorig
and M.
Fujihira
, Appl. Phys. Lett.
77
, 4211
(2000
).8.
D. B.
Romero
, M.
Schaer
, L.
Zuppiroli
, B.
Cesar
, and B.
Francois
, Appl. Phys. Lett.
67
, 1659
(1995
).9.
J.
Lee
, D. S.
Leem
, and J. J.
Kim
, Org. Electron.
9
, 805
(2008
).10.
S.
Seo
, T.
Sasaki
, N.
Sugisawa
, H.
Nowatari
, T.
Ushikubo
, Y.
Oe
, H.
Kadoma
, H.
Nakashima
, and N.
Ohsawa
, SID Int. Symp. Digest Tech. Papers
41
, 1804
(2010
).11.
C. C.
Chang
, M. T.
Hsieh
, J. F.
Chen
, S. W.
Hwang
, and C. H.
Chen
, Appl. Phys. Lett.
89
, 253504
(2006
).12.
S. D.
Cai
, C. H.
Gao
, D. Y.
Zhou
, W.
Gu
, and L. S.
Liao
, ACS Appl. Mat. Interfaces
4
, 312
(2012
).13.
H.
Ikeda
, J.
Sakata
, M.
Hayakawa
, T.
Aoyama
, T.
Kawakami
, K.
Kamata
, Y.
Iwaki
, S.
Seo
, Y.
Noda
, R.
Nomura
, and S.
Yamazaki
, SID Int. Symp. Digest Tech. Papers
37
, 923
(2006
).14.
J. H.
Lee
, D. S.
Leem
, H. J.
Kim
, and J. J.
Kim
, Appl. Phys. Lett.
94
, 123306
(2009
).15.
D. S.
Leem
, H. D.
Park
, J. W.
Kang
, J. H.
Lee
, J. W.
Kim
, and J. J.
Kim
, Appl. Phys. Lett.
91
, 011113
(2007
).16.
D. R.
Kearns
, G.
Tollin
, and M.
Calvin
, J. Chem. Phys.
32
, 1020
(1960
).17.
B.
Boudjema
, N.
El-Khatib
, M.
Gamoudi
, G.
Guillaud
, and M.
Maitrot
, Rev. Phys. Appl.
23
, 1127
(1988
).18.
M.
Maitrot
, G.
Guillard
, B.
Boudjema
, J. J.
Andre
, and J.
Simon
, J. Appl. Phys.
60
, 2396
(1986
).19.
X.
Zhou
, J.
Blochwitz
, M.
Pfeiffer
, A.
Nollau
, T.
Fritz
, and K.
Leo
, Adv. Funct. Mater.
11
, 310
(2001
).20.
J.
Blochwitz
, M.
Pfeiffer
, T.
Fritz
, and K.
Leo
, Appl. Phys. Lett.
73
, 729
(1998
).21.
M.
Pfeiffer
, A.
Beyer
, T.
Fritz
, and K.
Leo
, Appl. Phys. Lett.
73
, 3202
(1998
).22.
X.
Zhou
, M.
Pfeiffer
, J.
Blochwitz
, A.
Werner
, A.
Nollau
, T.
Fritz
, and K.
Leo
, Appl. Phys. Lett.
78
, 410
(2001
).23.
Y.
Yuan
, D.
Grozea
, and Z. H.
Lu
, Appl. Phys. Lett.
86
, 143509
(2005
).24.
S. H.
Cho
, S. W.
Pyo
, and M. C.
Suh
, Synth. Met.
162
, 402
(2012
).25.
S. H.
Cho
, S. M.
Lee
, and M.
Ch. Suh
, Org. Electron.
13
, 833
(2012
).26.
L. S.
Liao
and K. P.
Klubek
, Appl. Phys. Lett.
92
, 223311
(2008
).27.
L. S.
Liao
, W. K.
Slusarek
, T. K.
Hatwar
, M. L.
Ricks
, and D. L.
Comfort
, Adv. Mater.
20
, 324
(2008
).28.
See supplementary material at http://dx.doi.org/10.1063/1.4802081 for the details of absorption spectra, hole injeciton effiiciency calculations and barrier height fittting by a Schottky thermal emission model.
29.
S. D.
Ha
and A.
Kahn
, Phys. Rev. B
80
, 195410
(2009
).30.
S. D.
Ha
, J.
Meyer
, and A.
Kahn
, Phys. Rev. B
82
, 155434
(2010
).31.
P. N.
Murgatroyd
, J. Phys. D: Appl. Phys.
3
, 151
(1970
).32.
C. E.
Small
, S. W.
Tsang
, J.
Kido
, S. K.
So
, and F.
So
, Adv. Funct. Mater.
22
, 3261
(2012
).33.
J. C.
Scott
, J. Vac. Sci. Technol. A
21
, 521
(2003
).34.
35.
Y. K.
Kim
, J. W.
Kim
, and Y.
Park
, Appl. Phys. Lett.
94
, 063305
(2009
).36.
T.
Matsushima
, Y.
Kinoshita
, and H.
Murata
, Appl. Phys. Lett.
91
, 253504
(2007
).37.
S. T.
Lee
, Z. Q.
Gao
, and L. S.
Hung
, Appl. Phys. Lett.
75
, 1404
(1999
).© 2013 AIP Publishing LLC.
2013
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