ORGANIC
LETTERS
2004
Vol. 6, No. 20
3485-3487
Synthesis of Extremely Stable Blue
Light Emitting Poly(spirobifluorene)s
with Suzuki Polycondensation
Yonggang Wu, Jing Li, Yaqin Fu, and Zhishan Bo*
State Key Laboratory of Polymer Physics and Chemistry, CAS Key Lab of Organic
Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080, China
Received July 7, 2004
ABSTRACT
Full spirobifluorene-based blue light emitting polymers, which exhibited extraordinary thermal and color stability, were prepared with SPC
through an AB-type monomer route.
Polymer light emitting materials have received considerable
scientific and industrial attention due to their potential
application in large area flat-panel displays.1 For full-color
displays, three primary color emitting materials, i.e., blue,
green, and red, are required. High brightness and efficiency
and lifetimes of greater than 10 000 h have already been
achieved for green and red light emitting polymers. However,
as yet, no example of blue light emitting polymers fully meets
requirements for commercially feasible light emitting diodes.2
A challenging goal is to produce blue light emitting materials
with long-term stability and high efficiency and that are free
of blue-green emission. Highly soluble poly-2,7-(9,9-dialkyl)-
fluorenes (PFs) and their copolymers are considered as very
promising blue light emitting materials because of their
exceptionally high solid-state quantum yields not reached
with other conjugated polymers.3 Problems encountered with
these rodlike PFs and their copolymers are their color sta-
bility. A low energy green band emission is generated during
operation or annealing in air.4 In the literature, two popular
points of view (“aggregation or excimer formation” and “on-
chain defects”) on the origin of green band emission have
been proposed.4 Many studies have been done to understand
the origin of this green band emission and to search for
effective ways to suppress it.5
Compared with the huge amounts of publications on
fluorene polymers and copolymers, less attention was paid
to spirobifluorene polymers. Spirobifluorene building blocks
had been used by Salbeck et al. to construct blue light
emitting oligomers, dendrimers, and star-shaped molecules.6
Yu et al. showed that spirobifluorene-fluorene copolymers
exhibited better color stability than polyfluorenes.7 A mono-
(4) (a) Marsitzky, D.; Vestberg, R.; Blainey, P.; Tang, B. T.; Hawker,
C. J.; Carter, K. R. J. Am. Chem. Soc. 2001, 123, 6965. (b) Setayesh, S.;
Grimsdale, A. C.; Weil, T.; Enkelmann, V.; Mu¨llen, K.; Meghdadi, F.; List,
E. J. W.; Leising, G. J. Am. Chem. Soc. 2001, 123, 946. (c) Gaal, M.; List,
E. J. W.; Scherf, U. Macromolecules 2003, 36, 4236. (d) Lupton, J. M.;
Craig, M. R.; Meijer, E. W. Appl. Phys. Lett. 2002, 24, 4489.
(5) For example: (a) Surin, M.; Hennebicq, E.; Ego, C.; Marsitzky, D.;
Grimsdale, A. C.; Mu¨llen, K.; Bre´das, J.-L.; Lzzaroni, R.; Lecle`re, P. Chem.
Mater. 2004, 16, 994. (b) Li, J.; Bo, Z. S. Macromolecules 2004, 37, 2013.
(c) Gong, X.; Iyer, P. K.; Moses, D.; Bazan, G. C.; Heeger, A. J.; Xiao, S.
S. AdV. Funct. Mater. 2003, 13, 325.
(6) (a) Johansson, N.; D. Dos Santos, A.; Guo, S.; Cornil, J.; Fahlman,
M.; Salbeck, J.; Schenk, H.; Arwin, H.; Bredas, J. L.; Salanek, W. R. J.
Chem. Phys. 1997, 107, 2542. (b) Johansson, N.; Salbeck, J.; Bauer, J.;
Weisso¨rtel, F.; Bro¨ms, P.; Andersson A.; Salaneck, W. R. Synth. Met. 1999,
101, 405. (c) Speher, T.; Pudzich, R.; Fuhrmann, T.; Salbeck, J. Org.
Electron. 2003, 4, 61.
(1) (a) Burroughes, J. H.; Bradley, D. D. C.; Brown, A. B.; Marks, R.
N.; Mackay, K.; Friend, R. H.; Burn, P. L.; Holmes, A. B. Nature 1990,
347, 539. (b) Hide, F.; Diaz-Garcia, M. A.; Schwartz, B. J.; Heeger, A. J.
Acc. Chem. Res. 1997, 30, 430. (c) Mu¨ller, C. D.; Falcou, A.; Reckefuss,
N.; Rojahn, M.; Wiederhirn, V.; Rudati, P.; Frohne, H.; Nuyken, O.; Becker,
H.; Meerholz, K. Nature 2003, 421, 829.
(2) Jiang, X. Z.; Liu, S.; Ma, H.; Jen, A. K. Y. Appl. Phys. Lett. 2000,
76, 1813.
(3) (a) Leclerc, M. J. Polym. Sci. Part A: Polym. Chem. 2001, 39, 2867.
(b) Neher, D. Macromol. Rapid Commun. 2001, 22, 1365.
(7) Yu, W.-L.; Pei, J.; Huang, W.; Heeger, A. J. AdV. Mater. 2000, 12,
828.
10.1021/ol048709o CCC: $27.50
© 2004 American Chemical Society
Published on Web 08/31/2004