Halogen Precursor Route to Poly[(2,3-diphenyl-p-phenylene)vinylene] (DP-PPV):  Synthesis, Photoluminescence, Electroluminescence, and Photoconductivity

Abstract

Thin films of poly[(2,3-diphenyl-p-phenylene)vinylene] (DP-PPV) have been prepared via a chlorine precursor route (CPR). This involves the polymerization of 1,4-bis(chloromethyl)-2,3-diphenylbenzene with 1.0 equiv of potassium tert-butoxide to give the chlorine precursor polymer of DP-PPV. The chlorine precursor was thermally converted at different temperatures to give DP-PPV with different degrees of conversion. The conversion process was monitored by in situ photoluminescent (PL) spectroscopy. The onset of conversion was about 150 °C, and full conversion could be achieved at 170−250 °C. The degree of conversion was a function of the heating temperature rather than the duration of heating. The fully converted DP-PPV showed lower photoconductivity and higher PL intensity than PPV. Although partially converted DP-PPV showed bright PL, we have not been able to observe its EL. The electroluminescence (EL) of the single layer ITO/DP-PPV/Mg and the bilayer ITO/DP-PPV/Alq3/Mg LED devices is also reported. A significant improvement in the quantum efficiency (up to 0.7% ph/el) and a reduction in the turn-on voltage of the device were found upon incorporation of the Alq3 layer. These observations suggest that Alq3 enhances the injection of electrons and also participates in the recombination process.

Color-tunable multilayer light-emitting diodes based on conjugated polymers

“…1͑b͔͒ for G1, Dow Chemical LUMATION 16 Green-B polyfluorene ͑DPF͒ for G2, and poly͓9,9-di-͑2-ethylhexyl͒-fluorenyl-2.7-diyl͔ ͑BEHF͒ ͓Fig. 1͑c͔͒ for B. MEH-PPV and DP10-PPV are synthesized, 17,18 DPF is from Dow Chemical Company, 19 and BEHF is from Aldrich. The peaks of photoluminescence ͑PL͒ for the polymers are 592 nm ͑R͒, 500 nm ͑G1͒, 540 nm ͑G2͒, and 424 nm ͑B͒.…”

Progress in Polymeric Electron-Donating Materials for Organic Solar Cells

“…2-methoxy-5-(2'-ethylhexyloxy)] [8] [14] . 一般 PPV 类 聚合物是 p 型半导体材料, 而 Heeger 等 [15] 将强吸电子能 力的 CN 基团引入 PPV 主链, 得到 n 型的聚合物半导体 材料 CN-PPV.…”

Liquid crystalline conjugated polymers and their applications in organic electronics

“…Many synthetic routes have been proposed and widely used to prepare PPV derivatives, including Wessling and Zimmerman route, 7 Gilch route, 8 chlorine precursor route, 9 Heck coupling polymerization, 10 Wittig condensation, 11 and Knoevenagel polycondensation. 12 Because long alkyl chains or mesogenic groups are incorporated onto the monomer structure before polymerization, the forming polymers are usually soluble in common organic solvents.…”

“…In 1997, Hsieh and coworkers 9 proposed a synthetic route to poly(2,3-diphenyl-1,4-phenylenevinylene) (DP-PPV), which exhibits high photoluminescence (PL) efficiency in the solid state. Different substituents can be introduced on the 5-position of the phenyl ring to improve its properties.…”