d (TMS, ppm): 14.0, 20.7, 29.7, 31.3, 110.1, 118.7, 123.3, 126.3,
by a one-pot Suzuki coupling reaction through the ‘‘A2 + B4’’
approach. The obtained polymer exhibited good thermal
stability and excellent fluorescent stability in the solid state. Due
to its AIEE features, HP-TPE-Cz was able to act as an explosive
chemosensor both in the aggregate and solid state, for practical
application, and its sensitivity was much higher than its linear
analog LP-TPE-Cz, which also contained TPE units and
carbazole moieties. PLED devices (ITO/PEDOT:PSS (25 nm)/
Poly-TPD (25 nm)/HP-TPE-Cz or LP-TPE-Cz (32 nm)/TPBI
(35 nm)/Cs2CO3 (8 nm):Ag (100 nm)) have been fabricated to
investigate their electroluminescent properties. Interestingly, the
HP-TPE-Cz-based device showed a maximum luminescence of
5914 cd mꢀ2, with a maximum luminescence efficiency of 2.13 cd
Aꢀ1, which was much higher than LP-TPE-Cz and even most
other conjugated hyperbranched polymers.
127.6, 128.6, 131.4, 131.8, 140.5, 141.6, 143.8.
Synthesis of LP-TPE-Cz
A mixture of carbazole-based A2-type monomer S5 (114.3 mg,
0.30 mmol), TPE-containing B2-type monomer S3 (175.3 mg,
0.30 mmol), potassium carbonate (828.0 mg, 6.0 mmol), THF
(7.5 mL)–water (1.5 mL), and Pd(PPh3)4 (4.8 mg) was carefully
degassed and charged with argon. Then the reaction mixture was
stirred at 60 ꢁC for 3 days. Then, the trace end groups were
capped by refluxing for 12 h with phenylboronic acid and bro-
mobenzene, sequentially. An excess of methanol was poured into
the mixture, then it was filtered. The obtained solid was dissolved
in THF, and the insoluble solid was filtered out. After removal of
the solvent, the residue was further purified by several precipi-
tations from THF into acetone, and the obtained solid was then
washed with an excess of acetone and dried in a vacuum at 40 ꢁC
to a constant weight. The resultant polymer was obtained as
a yellow powder (105.1 mg, 63.4%). Mw ¼ 9700, Mw/Mn ¼ 1.77
(GPC, polystyrene calibration). IR (KBr), y (cmꢀ1): 1601 (C]C).
1H NMR (300 MHz, CDCl3, 298 K), d (TMS, ppm): 0.8–1.0
(–CH3), 1.2–1.5 (–CH2–), 1.7–2.0 (–CH2–), 4.2–4.4 (–NCH2–),
6.8–7.8 (ArH), 8.2–8.4 (ArH). 13C NMR (75 MHz, CDCl3, 298
K), d (TMS, ppm): 14.2, 20.8, 31.4, 43.3, 109.2, 118.9, 123.7,
125.3, 126.5, 127.5, 128.4, 129.0, 131.8, 123.1, 139.9, 140.5, 140.8,
142.3, 144.3.
Acknowledgements
We are grateful to the National Science Foundation of China
(no. 21034006), and the National Fundamental Key Research
Program (2011CB932702) for financial support.
Notes and references
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Fabrication and characterization of PLEDs
In a general procedure, indium-tin oxide (ITO)-coated glass
substrates were etched, patterned, and washed with detergent,
deionized water, acetone, and ethanol, sequentially. We fabri-
cated PLEDs using the two polymers HP-TPE-Cz or LP-TPE-Cz
as the emissive layer witha structure of ITO/PEDOT:PSS (25 nm)/
Poly-TPD (25 nm)/EML (32 nm)/TPBI (35 nm)/Cs2CO3
(8 nm):Ag (100 nm), where PEDOT:PSS, Poly-TPD and TPBI
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and hole-blocking/electron-transporting layers, respectively. The
active layer was spin-coated from chlorobenzene solution and
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PR650 photometer. Current density–voltage–luminance (J–V–L)
measurements were made simultaneously using a Keithley 4200
semiconductor parameter analyzer and a Newport multifunction
2835-C optical meter, with luminance measured in the forward
direction. All device characterizations were carried out under
ambient laboratory air at room temperature.
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Conclusions
In this paper, a new hyperbranched polymer HP-TPE-Cz, con-
structed of carbazole and TPE units, was conveniently prepared
This journal is ª The Royal Society of Chemistry 2012
J. Mater. Chem., 2012, 22, 6374–6382 | 6381