Abstract: A kind of soluble electroluminescent polymer poly(2,5-diheptoxy-1,4-phenylenevinylene)(PDHPV)was synthesized and its electroluminescence(FL)properties were investigated. Amilder condition in the synthesis of the MeO-precursor was found,i.e.MeOH-H₂O mixed solvents can turn the sulfonium precursor into MeO-precursor at ambient temperature, Two kinds of devices were fabricated by drop coating: ITO/PDHPV/AL,ITO/PDHPV/Alq3/Al(Alq3:8-hydroxyquinoline aluminium).The luminescence spectra produced in these devices are essentially the same as that of the photoluminescence(PL)of PDHPV. The Alq3 layer acts as the electron-conducting, hole-blocking layer, The efficiency and brightness of the double-layer device was improved. Compared with the analogous double-layer device fabricated with PPV and Alq3: ITO/PPV/Alq3/Al, a strange phenomenon was observed, Alq3 instead of PPVemits light, this is due to the wider band gap of PPV (2.5 eV)than that of PDHPV(2.1 eV) which blocks the creaticn of the singlet excitons in the polymer layer. The band gap of PDHPV narrower than that of PPV makes the radiative decay occur in the PDHPV layer instead of Alq3 layer. The double-layer device has a betterstability.

Key words: PDHPV conjugated polymer, Electroluminescence, Electron-transporting layer, Hole-transporting layer