The use of alkali metal compound/Al bilayer cathodes of LiF/Al and Liq/Al caused a dramatic luminous efficiency change of one order of magnitude in organic light-emitting diodes (OLEDs) comprising 2-methyl-9,10-bis(naphthalene-2-yl)anthracene (MADN) as an electron-transporting layer (ETL). In contrast, the use of the same two electrodes yielded similar efficiency in OLEDs comprising of tris(8-hydroxyquinoline) aluminum(III) (Alq3) as an ETL. The dramatic change is attributed to different behaviors of LiF/Al and Liq/Al cathodes toward the ETL. It is revealed that organic alkali metal complex/Al, such as Liq/Al, is superior to inorganic alkali metal compound/Al, such as LiF/Al, as a standard bilayer cathode to investigate the effectiveness of electron-transporting materials for high-efficiency OLEDs.

1.
L. S.
Hung
,
C. W.
Tang
, and
M. G.
Mason
,
Appl. Phys. Lett.
70
,
152
(
1997
).
2.
G. E.
Jabbour
,
B.
Kippelen
,
N. R.
Armstrong
, and
N.
Peyghambarian
,
Appl. Phys. Lett.
73
,
1185
(
1998
).
3.
X. H.
Yang
,
Y. Q.
Mo
,
W.
Yang
,
G.
Yu
, and
Y.
Cao
,
Appl. Phys. Lett.
79
,
563
(
2001
).
4.
J.
Huang
,
G.
Li
,
E.
Wu
,
Q.
Xu
, and
Y.
Yang
,
Adv. Mater. (Weinheim, Ger.)
18
,
114
(
2006
).
5.
T.
Wakimoto
,
Y.
Fukuda
,
K.
Nagayama
,
A.
Yokoi
,
H.
Nakada
, and
M.
Tsuchida
,
IEEE Trans. Electron Devices
44
,
1245
(
1997
).
6.
J.
Endo
,
J.
Kido
, and
T.
Matsumoto
,
Proceedings of the International Conference on Advanced Technology of Polymers
, Yamagata, Japan,
1999
, p.
124
.
7.
X.
Zheng
,
Y.
Wu
,
R.
Sun
,
W.
Zhu
,
X.
Jiang
,
Z.
Zhang
, and
S.
Xu
,
Thin Solid Films
478
,
252
(
2005
).
8.
S. H.
Kim
,
J.
Jang
, and
J. Y.
Lee
,
Appl. Phys. Lett.
91
,
103501
(
2007
).
9.
J.
Endo
,
T.
Matsumoto
, and
J.
Kido
,
Extended Abstracts of the Ninth International Workshop on Inorganic and Organic Electroluminescence
,
1998
, p.
57
.
10.
K.
Xie
,
J.
Qiao
,
L.
Duan
,
Y.
Li
,
D. Q.
Zhang
,
G. F.
Dong
,
L. D.
Wang
, and
Y.
Qiu
,
Appl. Phys. Lett.
93
,
183302
(
2008
).
11.
C. W.
Tang
and
S. A.
VanSlyke
,
Appl. Phys. Lett.
51
,
913
(
1987
).
12.
M. G.
Mason
,
C. W.
Tang
,
L. S.
Hung
,
P.
Raychaudhuri
,
J.
Madathil
,
L.
Yan
,
Q. T.
Le
,
Y.
Gao
,
S. T.
Lee
,
L. S.
Liao
,
L. F.
Cheng
,
W. R.
Salaneck
,
D. A.
dos Santos
, and
J. L.
Bredas
,
J. Appl. Phys.
89
,
2756
(
2001
).
13.
K. L.
Wang
,
B.
Lai
,
M.
Lu
,
X.
Zhou
,
L. S.
Liao
,
X. M.
Ding
,
X. Y.
Hou
, and
S. T.
Lee
,
Thin Solid Films
363
,
178
(
2000
).
14.
L. S.
Liao
and
K. P.
Klubek
,
Appl. Phys. Lett.
92
,
223311
(
2008
).
15.
L. S.
Liao
,
X.
Ren
,
W. J.
Begley
,
Y. S.
Tyan
, and
C. A.
Pellow
,
SID Int. Symp. Digest Tech. Papers
39
,
818
(
2008
).
16.
H.
Aziz
,
Z. D.
Popovic
,
S.
Xie
,
A.
Hor
,
N.
Hu
,
C. P.
Tripp
, and
G.
Xu
,
Appl. Phys. Lett.
72
,
756
(
1998
).
17.
L. S.
Liao
,
X. H.
Sun
,
L. F.
Cheng
,
N. B.
Wong
,
C. S.
Lee
, and
S. T.
Lee
,
Chem. Phys. Lett.
333
,
212
(
2001
).
18.
P.
Lu
,
H. P.
Hong
,
G. P.
Cai
,
P.
Djurovich
,
W. P.
Weber
, and
M. E.
Thompson
,
J. Am. Chem. Soc.
122
,
7480
(
2000
).
19.
L. S.
Liao
,
W. K.
Slusarek
,
T. K.
Hatwar
,
M. L.
Ricks
, and
D. L.
Comfort
,
Adv. Mater. (Weinheim, Ger.)
20
,
324
(
2008
).
20.
M. T.
Lee
,
C. H.
Liao
,
C. H.
Tsai
, and
C. H.
Chen
,
Adv. Mater. (Weinheim, Ger.)
17
,
2493
(
2005
).
21.
A.
Fukase
and
J.
Kido
,
Jpn. J. Appl. Phys., Part 2
41
,
L334
(
2002
).
22.
S. K.
Saha
,
Y. K.
Su
, and
W. L.
Lin
,
EPL
85
,
18002
(
2009
).
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