| Since the first report of light-emitting polymer based on poly(p-phenylenevinylene) (PPV) by Cambridge group in 1990, light-emitting polymers materials and their luminescent device have been attracted wide research interests in materials science and display technology field. Due to structural diversity, good processability, facile color tunability, high luminescence efficiencies and so on, PPV derivatives are still one of the most popular class of conjuguated polymers used as active material in PLEDs. This dissertation have been systematically reviewed the research progress of polymer light-emitting diode (PLED) and light-emitting polymers materials. Especially, PPV derivatives whose structure modified by introducing side or main chain were discussed in detail.In this dissertation, we have designed and synthesized a novel"p-n block"type PPV derivative, poly [5,8-quinolinenevinylene-(2-methoxy-5-octyloxy)-p-phenylenevinylene] (PQV-alt-MOPPV). The main contents of this dissertation are as follows:1. Monomer 5,8-bis(bromomethyl)quinoline, 2-methoxy-5-octyloxy-1,4-bis(chloro- methyl)benzene, 2-methoxy-5-octyloxyterephthalaldehyde, 5,8-(bismethylene)-quinoline bis- (triphenylphosphonium bromide) and 5,8-bis(diethoxyphosphorylmethyl)-quinoline were synthesized from basic organic materials. The structures of the synthesized monomers and the intermediates were identified by 1H NMR. All rection procedure conditions were optimized and the preferable results were obtained.2. Copolymers of 5,8-quinolinenevinylene and 2-methoxy-5-octyloxy-p-phenylenevinylene were synthesized, respectively, by Gilch polymerization, phase transfer catalysis, Wittig and Wittig-Horner condensation polymerization based on corresponding monomers. The solubility and GPC measurement of the resulting copolymers indicated that the alternating copolymers, PQV-alt-MOPPV prepared by Wittig-Horner condensation polymerization possesed good solubility, high molecular weight, and narrow polydispersity index (PDI).3. The structures characterization of the obtained PQV-alt-MOPPVs by elemental analysis, FT-IR and 1H NMR showed that the obtained polymer was one class of all trans-configuration copolymer with high purity and regular structure. The thermal stability, optical and electrochemical properties of the copolymer were examined by DSC, TGA, UV-vis absorption, photoluminescence (PL), and cyclic voltammetry (CV). The results of DSC and TGA indicated that PQV segments introduced into polymer backbone improved the thermal stability of the copolymer, the Td and Tg of the copolymer were higher than that of homopolymer MO-PPV reported in literature, it is beneficial to PLED's fabrication and stability. The results of UV-vis absorption and PL indicated that the emission of copolymer solution and thin film states were located in red-light area, and the emission peaks values were 571 and 629 nm, respectively; with small Egopt value of 2.00 eV. The CV results showed that the LUMO of PQV-alt-MOPPV was modified to be -3.30 eV, indicating that its electron inject/transport properties had been greatly improved; its Egele agreed with Egopt very well, was 2.00 eV, too. All the results of mensurements demonstrated that the synthesized PQV-alt-MOPPV was one excellent light-emitting material.4. The single-layer PLED based on PQV-alt-MOPPV with the configuration of ITO/PEDOT:PSS/PQV-alt-MOPPV/Ca/Al emitted pure red light, its CIE chromaticity coordinates were (x = 0.64, y = 0.36); device's turn-on voltage was just 2.8 V; the maximum brightness was 188 cd/m2 at 5.2 V; the maximum luminescence efficiency of polymer was approximately 0.01 cd/A at 5.2 V and 0.0062 lm/w at 5.0 V. |
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