Fluorinated Poly(p-phenylenevinylene) Copolymers:  Preparation and Use in Light-Emitting Diodes

Abstract

A fluorinated poly(p-phenylenevinylene) analogue, co(TFPV-PV), has been prepared by copolymerization of fluorinated and nonfluorinated bissulfonium salt monomers. Conversion and yield decreased as a function of fluorine substitution. The UV-vis absorption was strongly shifted to the blue with increasing fluorine content. Complementary shifts in photoluminescence spectra were not observed, presumably because the fluorinated segments of the copolymer are very weakly luminescent relative to nonfluorinated segments. The photoluminescence spectra are therefore similar to those found for poly(p-phenylenevinylene) in the past. The co(TFPV-PV) compounds showed electroluminscence at an ac potential of ∼10 V (rms, 600 Hz) between ITO and Al electrodes. Maxima were shifted slightly to the blue with an increase in fluorine.

Light Emitting Properties of Fluorine-Substituted Poly(1,4-phenylene vinylenes)

“…They noted that PPVF4 blocks apparently have an EL efficiency similar to that of the PPV blocks, but the higher threshold function for PPVF4 blocks makes these weak EL emitting chromophores in the copolymer. 19 The net effect for PPV-co-PPVF4 with increasing PPVF4 content was a blue shift of about 60 nm in the UV absorption maximum relative to PPV but only about 5 nm in the EL spectrum. Thus, the behavior of this copolymer is dominated by PPV EL behavior and only indirectly affected by the PPVF4 blocks.…”

Pressure effect on photoluminescence and Raman spectra of PPV

“…The conjugated polymers, especially poly (paraphenylenevinylene) (PPV) and its derivatives, have attracted tremendous interest due to their potential applications in electronic and optical-electronic devices [1], such as the photo-active layer in light emitting diodes [2][3][4], lasers [5,6], and photovoltaic cell [7]. The synthetic routes via a soluble precursor polymer and groups containing either dimethyl sulfonium [8] or tetrahydrothiophenium [9] are beneficial for the process ability of the PPV film.…”

Stability of electroluminescent conjugated with fluoro groups in vinylene units

“…It was shown by Bredas et al that introduction of electron-withdrawing groups onto the arylene rings or the vinyl groups of PPV lowers the HOMO and LUMO energies of the polymer, thereby permitting the use of a higher work function metal in the LED device. 8 Numerous derivatives of PPV have been reported with electronwithdrawing substituents such as halide, [9][10][11][12][13] cyano, 14 trifluoromethyl, 15 or methylsulfonyl-phenyl 16 on the arylene rings. Other examples with electron withdrawing groups on vinylene group of conjugated polymers have also been reported.…”