Synthesis, Characterization, and Optoelectronic Properties of a Novel Polyfluorene/Poly(p-Phenylenevinylene) Copolymer

Abstract

A novel conjugated polyfluorene/poly(p-phenylenevinylene) copolymer containing the pendant bis(4-alkoxyphenyl) groups in the C-9 position of every alternating fluorene unit has been synthesized and well structurally characterized. The photoluminescence spectrum of this polymer exhibits strong concentration and excitation wavelength dependence in solution. The excited triplet-state maximum of polymer occurs in the region of 460−540 nm with a lifetime of 65.8 μs. This copolymer displays a minor positive nonlinear absorption at the focus of the laser irradiation, suggesting possible reverse saturable absorption. The stable electroluminescent spectrum of the polymer light-emitting diode device based on this copolymer (device configuration, indium−tin oxide/Au/copolymer/LiF/Al) was obtained with a peak wavelength of 515 nm. The bright-green emission observed over the whole active area of the copolymer closely resembles the photoluminescence of the most concentrated solution (0.5 M) used. This suggests that chain stacking in the solid state is responsible for the observed green electroluminescence.

Synthesis and Characterization of a New Triphenylamine-Substituted PFO/PPV Copolymer

“…The sample was heated to 500 C in flowing (100 mLÁmin À1 ) dry nitrogen atmosphere. The weight loss of the polymer was less than 10% until upon heating to 300 C; its onset temperature for the thermal bond cleavage is at 178 C. In contrast to the polymer 2, the TGA thermogram of the PFO/ PPV alternative copolymer 15 exhibits two weight-loss plateaus. At lower temperatures almost no weight loss was observed.…”

“…In our previous work, 15 we designed and prepared a novel conjugated PFO/ PPV copolymer containing the pendant bis(4-alkoxyphenyl) groups in the C-9 position of every fluorene unit (Figure 1) through a typical Heck-couping reaction. The facile functionalization at the C-9 position of the fluorene unit may offer an opportunity to reduce the interchain interactions thereby improving the optoelectronic properties of the resulting polymers.…”

A new blue‐light emitting polymer: Synthesis and photoinduced electron transfer process

“…Among the large number of blue-light emitting polymers [5][6][7] that have been identified, polyfluorenes (PFs) have emerged as one of the most promising materials owing to their high photoluminescence quantum yields, good charge transport properties, better thermal and chemical stability, and the facile functionalization at the C-9 position of the fluorene unit which may offer an opportunity to reduce the interchain interactions thereby improving the optoelectronic properties of the resulting polymers. 8 The biggest disadvantage of PFs lies in their poor spectral stability and low electroluminescence efficiency as a result of keto-defects generated by the oxidation of monoalkyfluorenes. 9 As one of the useful hole transporting materials, triphenylamine (TPA) and its organic and polymeric derivatives have been widely used in OLEDs and PLEDs.…”

Novel oligomers based on fluorene and 2,4‐difluorobenzene: Correlation between the structures and optical properties

“…So far, the most intensely investigated oligomers are linear, conjugated p systems, which are prone to aggregation and end up with self-quenching of their luminescence. [3][4][5][6][7][8][9][10] Therefore, the design and synthesis of fluorene-based oligomers with branched and welldefined frameworks are emerging. [11][12][13][14] Such materials are expected to be less aggregated and should not suffer from fluorescence quenching because of the bulky intermolecular interactions.…”