Steady state as well as time-resolved fluorescence of phenyl-substituted polyphenylenevinylene (PhPPV), both in solution and in form of spin-coated films has been measured. In solution the fluorescence decays exponentially with a 1/e decay time of ∼700 ps, whereas the 1/e decay in the film is ∼400 ps and the decay approaches a stretched exponential with an exponent of β=0.65. Doping the film with various amounts of trinitrofluorenone (TNF) shortens the decay time without changing the form of the Kohlrausch–Williams–Watts decay law. This is a signature of exciton dissociation in a random polymer matrix through electron transfer to TNF. The data analysis shows that “neat” PhPPV contains a concentration of ⩽ 0.04 wt. % of unidentified electron scavengers. A hypsochromic shift of the cw fluorescence spectra in doped films is interpreted in terms of increasingly frustrated spectral relaxation of singlet excitations within the inhomogeneously broadened distribution of hopping states.

1.
D. J.
Pinner
,
R. H.
Friend
, and
N.
Tessler
,
J. Appl. Phys.
86
,
5116
(
1999
).
2.
P. W. M.
Blom
and
M. C. J. M.
Vissenberg
,
Mater. Sci.
27
,
53
(
2000
).
3.
P. K. H.
Ho
,
J. S.
Kim
,
J. H.
Burroughes
,
H.
Becker
,
S. F. Y.
Li
,
M.
Brown
,
F.
Cacialli
, and
R. H.
Friend
,
Nature (London)
404
,
481
(
2000
).
4.
J. M.
Lupton
,
B. J.
Matterson
,
I. D. W.
Samuel
,
M. J.
Jory
, and
W. L.
Barnes
,
Appl. Phys. Lett.
77
,
3340
(
2000
).
5.
U.
Lemmer
,
R. F.
Mahrt
,
Y.
Wada
,
A.
Greiner
,
H.
Bässler
, and
E. O.
Göbel
,
Appl. Phys. Lett.
62
,
2827
(
1993
).
6.
P.
Schouwink
,
G.
Gadret
, and
R. F.
Mahrt
,
Chem. Phys. Lett.
341
,
213
(
2001
).
7.
H.
Becker
,
H.
Spreitzer
,
W.
Kreuder
,
E.
Kluge
,
H.
Schenk
,
I.
Parker
, and
Y.
Cao
,
Adv. Mater.
12
,
42
(
2000
).
8.
H. Spreitzer, W. Kreuder, H. Becker, H. Schenk, and N. Yu, PCT Patent Application WO99/24526 (1997).
9.
S.
Heun
,
R. F.
Mahrt
,
A.
Greiner
,
U.
Lemmer
,
H.
Bässler
,
D. A.
Halliday
,
D. D. C.
Bradley
,
P. L.
Burn
, and
A. B.
Holmes
,
J. Phys.: Condens. Matter
5
,
247
(
1993
).
10.
I. D. W.
Samuel
,
G. R.
Rumbles
, and
A. J.
Collison
,
Phys. Rev. B
52
,
11573
(
1995
).
11.
R. I. Personov, in Spectroscopy and Excitation Dynamics of Condensed Molecular Systems, edited by V. M. Agranovich and R. M. Hochstrasser (North-Holland, Amsterdam, 1983), p. 535.
12.
B.
Mollay
,
U.
Lemmer
,
R.
Kersting
,
R. F.
Mahrt
,
H.
Kurz
,
H. F.
Kauffmann
, and
H.
Bässler
,
Phys. Rev. B
50
,
10769
(
1994
).
13.
I. B. Berlman, in Handbook of Fluorescence Spectra of Aromatic Molecules, 2nd ed. (Academic, New York, 1971), p. 15.
14.
T.
Ueda
,
R.
Fujisawa
,
H.
Fukumura
,
A.
Itaya
, and
H.
Masuhara
,
J. Phys. Chem.
99
,
3629
(
1995
).
15.
J.
Klafter
and
A.
Blumen
,
Chem. Phys. Lett.
119
,
377
(
1985
).
16.
A.
Kadashchuk
,
Yu.
Skryshevskii
,
A.
Vakhnin
,
N.
Ostopenko
,
V. I.
Arkhipov
,
E. V.
Emelianova
, and
H.
Bässler
,
Phys. Rev. B
63
,
115205
(
2001
).
17.
R.
Richert
and
H.
Bässler
,
J. Chem. Phys.
84
,
3567
(
1986
).
18.
K.
Brunner
,
A.
Tortschanoft
,
Ch.
Warmuth
,
H.
Bässler
and
H. F.
Kauffmann
,
J. Phys. Chem. B
104
,
3781
(
2000
).
19.
R. F.
Mahrt
,
T.
Pauck
,
U.
Lemmer
,
U.
Siegner
,
M.
Hopmeier
,
R.
Hennig
,
H.
Bässler
, and
E. O.
Göbel
,
Phys. Rev. B
54
,
1759
(
1996
).
20.
B.
Movaghar
,
M.
Grünewald
,
B.
Ries
,
H.
Bässler
, and
D.
Würtz
,
Phys. Rev. B
33
,
5545
(
1986
).
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