Time-of-flight measurements have been used to study carrier transport in films of poly(9,9-dioctylfluorene). We find nondispersive hole transport with a room-temperature mobility, μp=4×10−4cm2/V s at a field of 5×105V/cm. The field dependence of the mobility is weak: μp=3×10−4cm2/V s at 4×104V/cm and increases only modestly to μp=4.2×10−4cm2/V s at 8×105V/cm. Both the relatively high mobility and weak field dependence point to a high degree of chemical regularity and purity that makes polyfluorene attractive for use as an electroluminescent polymer and for other device applications. We have not been able to measure clean electron current transients, suggesting highly dispersive transport with possible deep trapping, as found in many other conjugated polymers.

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
).
2.
D. D. C.
Bradley
,
Curr. Opin. Solid State Mater. Sci.
1
,
789
(
1996
).
3.
G.
Grem
,
G.
Leditzky
,
B.
Ullrich
, and
G.
Leising
,
Adv. Mater.
4
,
36
(
1992
).
4.
Q.
Pei
and
Y.
Yang
,
J. Am. Chem. Soc.
118
,
7416
(
1996
);
H. N.
Cho
,
D. Y.
Kim
,
Y. C.
Kim
,
J. Y.
Lee
, and
C. Y.
Kim
,
Adv. Mater.
9
,
326
(
1997
);
D. D. C.
Bradley
,
M.
Grell
,
X.
Long
,
H.
Mellor
,
A.
Grice
,
M.
Inbasekaran
, and
E. P.
Woo
,
Proc. SPIE
3145
,
254
(
1997
);
M.
Ranger
,
D.
Rondeau
, and
M.
Leclerc
,
Macromolecules
30
,
7686
(
1997
).
5.
M.
Grell
,
D. D. C.
Bradley
,
M.
Inbasekaran
, and
E. P.
Woo
,
Adv. Mater.
9
,
798
(
1997
).
6.
M. Grell, D. D. C. Bradley, X. Long, T. Chamberlain, M. Inbasekaran, E. P. Woo, and M. Soliman, Acta Polym. (to be published).
7.
S. Janietz, D. D. C. Bradley, M. Grell, M. Inbasekaran, and E. P. Woo (unpublished).
8.
A. W.
Grice
,
D. D. C.
Bradley
,
M. T.
Bernius
,
M.
Inbasekaran
,
W. W.
Wu
, and
E. P.
Woo
,
Appl. Phys. Lett.
73
,
629
(
1998
).
9.
N.
Tessler
,
G. J.
Denton
, and
R. H.
Friend
,
Nature (London)
382
,
695
(
1996
);
F.
Hide
,
M. A.
Diaz-Garcia
,
B. J.
Schwartz
,
M. R.
Andersson
,
Q.
Pei
, and
A. J.
Heeger
,
Science
273
,
1833
(
1996
);
W.
Holzer
,
A.
Penzkofer
,
S.-H.
Gong
,
A.
Bleyer
, and
D. D. C.
Bradley
,
Adv. Mater.
8
,
974
(
1996
).
10.
N.
Miyaura
and
A.
Suzuki
,
Chem. Rev.
95
,
2457
(
1995
).
11.
D. G. Lidzey, A. Grice, M. Grell, and D. D. C. Bradley (unpublished).
12.
H.
Bässler
,
Phys. Status Solidi B
175
,
15
(
1993
).
13.
P. M. Borsenberger and D. S. Weiss, Organic Photoreceptors for Imaging Systems (Marcel Dekker, New York, 1993).
14.
Y.
Shirota
,
Y.
Kuwabara
,
H.
Inada
,
T.
Wakimoto
,
H.
Nakada
,
Y.
Yonemoto
,
S.
Kawami
, and
K.
Imai
,
Appl. Phys. Lett.
65
,
807
(
1994
).
15.
H.
Antoniadis
,
M. A.
Abkowitz
, and
B. R.
Hsieh
,
Appl. Phys. Lett.
65
,
2030
(
1994
).
16.
H.
Meyer
,
D.
Haarer
,
H.
Naarmann
, and
H.-H.
Hörhold
,
Phys. Rev. B
52
,
2587
(
1995
).
17.
W.
Warta
,
R.
Stehle
, and
N.
Karl
,
Appl. Phys. A: Solids Surf.
36
,
163
(
1985
).
18.
P. W. M.
Blom
,
M. J. M.
de Jong
, and
J. J. M.
Vleggaar
,
Appl. Phys. Lett.
68
,
3308
(
1996
).
19.
W.
Brütting
,
E.
Lebedev
,
S.
Karg
,
T.
Dittrich
,
V.
Petrova-Koch
, and
M.
Schwoerer
,
Proc. SPIE
3281
,
257
(
1998
).
20.
M.
Gailberger
and
H.
Bässler
,
Phys. Rev. B
44
,
8643
(
1991
).
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