Efficient green light-emitting polymer by balanced injection of electron and hole: new electron accepting perfluorinated substituent

We synthesized a new electron withdrawing group, perfluorinated aryl substituted PPV derivative via Wessling-Zimmerman polymerization in methanol. The synthesized precursor of poly[2-{(2,3,4,5,6-pentafluorobenzene)-2,3,5,6,-tetraflourophenyl}-1,4-phenylenevinylene] (PPFPV) showed good solubility in common organic solvents such as chloroform, methylenechloride, xylene, tetrahydrofuran. The molar mass measured by gel permeation chromatography (GPC) was M-w = 72,000. PPFPV showed the PL and EL emission maxima of 520 nm corresponding to green light, because of the strong electron-withdrawing effect: of the perfluorinated aryl group. The PPFPV single layer EL device showed 64 times higher EL efficiency than that of PPV with higher turn-on voltage. But, ITO/PPV/PPFPV/Al bilayer EL device showed about 380-fold higher EL efficiency compared with PPV, and its turn-on voltage was lowered to the PPV level. (C) 2000 Elsevier Science Ltd. All rights reserved.