Photoluminescence and electroluminescence (EL) from a conjugated dendrimer consisting of three distyrylbenzene units linked by a central nitrogen atom as core and meta-linked biphenyl units as dendrons were investigated. The conjugated dendrimer emits green light and shows photoluminescence quantum efficiency of 9%. Bright electroluminescence was realized by using bilayer devices with blurred interface, which were fabricated by sequentially spin coating a neat dendrimer and a dendrimer doped with 2-(4-biphenyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (PBD). The devices have the following structure: indium tin oxide/3,4-polyethylenedioxythiothene-polystyrenesulfonate/dendrimer/ dendrimer:PBD/Al. By optimizing the concentration of PBD, the maximum brightness and EL quantum efficiency reach 4100 cd/m2 and 0.17%, respectively. This is the best result reported so far on organic light-emitting diodes using dendrimer as an active material with an Al cathode.

1.
J. H.
Burroughes
,
D. D. C.
Bradley
,
A. R.
Brown
,
R. N.
Marks
,
K.
Mackay
,
R. H.
Friend
,
P. L.
Burn
, and
A. B.
Holmes
,
Nature (London)
347
,
539
(
1990
).
Google Scholar
 
2.
M. D.
McGehee
and
A. J.
Heeger
,
Adv. Mater.
12
,
1655
(
2000
).
Google Scholar
 
3.
R.
Jakubiak
,
C. J.
Collison
,
W. C.
Wan
,
L. J.
Rothberg
, and
B. R.
Hsieh
,
J. Phys. Chem. A
103
,
2394
(
1999
).
Google Scholar
 
4.
S.
Tasch
,
E. J. W.
List
,
O.
Ekström
,
W.
Graupner
,
G.
Leising
,
P.
Schlichting
,
U.
Rohr
,
Y.
Geerts
,
U.
Scherf
, and
K.
Mullen
,
Appl. Phys. Lett.
71
,
2883
(
1997
).
Google Scholar
 
5.
J.
Kido
,
M.
Kimura
, and
K.
Kagai
,
Science
267
,
1332
(
1995
).
Google Scholar
 
6.
M.
Halim
,
J. N. G.
Pillow
,
I. D. W.
Samuel
, and
P. L.
Burn
,
Adv. Mater.
11
,
371
(
1999
).
Google Scholar
 
7.
J. M.
Lupton
,
R.
Beavington
,
M. J.
Frampton
,
P. L.
Burn
,
I. D. W.
Samuel
, and
H.
Bässler
,
Phys. Rev. B
63
,
155206
(
2001
).
Google Scholar
 
8.
A. W.
Freeman
,
S. C.
Koene
,
P. R. L.
Malenfant
,
M. E.
Thompson
, and
J. M. J.
Fréchet
,
J. Am. Chem. Soc.
122
,
12385
(
2000
).
Google Scholar
 
9.
A.
Otomo
,
S.
Yokoyama
,
J.
Nakahama
, and
S.
Mashiko
,
Appl. Phys. Lett.
77
,
3881
(
2000
).
Google Scholar
 
10.
C. J.
Hawker
and
J. M. J.
Fréchet
,
J. Am. Chem. Soc.
112
,
7638
(
1990
).
Google Scholar
 
11.
A.
Adronov
,
S. L.
Gilat
,
J. M. J.
Fréchet
,
K.
Ohta
,
F. V. R.
Neuwahl
, and
G. R.
Heming
,
J. Am. Chem. Soc.
122
,
1175
(
2000
).
Google Scholar
 
12.
D.
Ma
,
J. M.
Lupton
,
R.
Beavington
,
P. L.
Burn
, and
I. D. W.
Samuel
,
Adv. Funct. Mater.
12
,
507
(
2002
).
Google Scholar
 
13.
J. N. G.
Pillow
,
M.
Halim
,
J. M.
Lupton
,
P. L.
Burn
, and
I. D. W.
Samuel
,
Macromolecules
32
,
5985
(
1999
).
Google Scholar
 
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