New orange-red light emitting diode from poly[2-(5-cyclohexylmethoxypentyloxy)-5-methoxy-1,4-phenylenevinylene]

Poly [2-(5-cyclohexylmethoxypentyloxy)-5-methoxy-1,4-phenylenevinylene] (PM CYHPV) was synthesized through dehydrohalogenation polymerization. This pol ymer shows good solubility in common organic solvents. The absorption and p hotoluminescence (PL) emission maxima of PMCYHPV are 497 nm and 590;nm, res pectively. The electroluminescence (EL) properties of poly[2-methoxy-5-(2-e thylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV) and PMCYHPV were studied by means of the EL spectra, current-voltage characteristics, and EL power-curr ent characteristics. The measured relative EL quantum efficiency of PMCYHPV is about 6 times higher than that of MEH-PPV. The EL enhancement of PMCYHP V originates from the reduction of non-radiative decay of excitons caused b y better separation of the polymer chains due to the rigid cyclohexyl side group. Furthermore, we found that the PL quantum efficiency of PMCYHPV is 1 5% higher than that of MEH-PPV.