THE SYNTHESIS OF PDHPV AND ITS ELECTROLUM INESCENT CHARACTERS

A kind of soluble electroluminescent polymer poly (2, 5-diheptoxy-11 4 -phenylenevinylene) (PDHPV) was synthesized and its electroluminescenc e (FL) properties were investigated, A milder condition in the synthes is of the MeO-precursor was found, i. e. MeOH-H2O mixed solvents can t urn the sulfonium precursor into MeO-precursor at ambient temperature, Two kinds of devices were fabricated by drop coating: ITO/PDHPV/Al, I TO/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 elect ron-conducting, hole-blocking layer, The efficiency and brightness of the double-layer device was improved. Compared with the analogous doub le-layer device fabricated with PPV and Alq3: ITO/PPV/Alq3/Al, a stran ge phenomenon observed, Alq3 instead of PPV emits light, this is due t o the wider band gap of PPV (2.5 eV) than that of PDHPV(2.1 eV) which blocks the creation 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 devic e has a better stability.