掺杂DCJTB聚合物电化学池(LEC)的发光性质

Light-emitting Properties of Electrochemical Cell(LEC) Based on Emitting Material Doped with DCJTB

通过在聚合物电化学池（LEC）发光器件的发光材料MEH-PPV中掺杂红光染料DCJTB，对LEC器件的发光性质进行研究。基于器件结构为ITO／MEH-PPV＋PEO＋LiCF3 SO3／Al的薄膜LEC器件，其电致发光峰在570nm左右，通过在MEH-PPV与PEO的混合膜中掺杂不同比例的红光染料DCJTB，随着掺杂比例的增加，器件的发光峰由570nm向红光波段移动，通过控制DCJTB的掺杂比例制备了发光峰在570-650nm连续变化的LEC电致发光器件。对其分析认为从LEC主体发光聚合物MEH-PPV到染料DCJTB间发生了良好的能量传递。

A polymer light-emitting electrochemical cell （LEC）offers an alternative approach to achieving electroluminescence （EL） from conjugated polymers. Different from a polymer light-emitting diode（ PLED）, the emitting layer of LEC contains ionic conductor such as poly （ ethylene oxide） （PEO） mixed with lithium salt. In these solid-state LECs, the conjugated polymers are p-doped on the anode side and n-doped on the cathode side and a light-emitting p-n junction is formed between the p-doped and n-doped regions. The LEC was shown to operate in both forward and reverse bias, effectively independent of the electrode workfunction. Compared with PLED, LEC has the advantages of low turn on voltage and high quantum efficiency of its electroluminescence. The luminescence of LEC based on emitting material poly[2-methoxy-5-（2＇-ethylhexyloxy）-1 ,4-phenylenevinylene] （ MEH-PPV ） doped with red dye 4-dicyanomethylene-2- （ tert-butyl ） -6-methyl-4H-pyran （ DCJTB ） has been researched. The EL peak wavelength of LEC devices depends on the luminescent materials of LEC. Usually OLEDs changed emission wavelength by doped organic dye into host materials, but this method in LEC was not reported. Doping organic dye into the luminescent materials of LEC may change the emission wavelength of device and fabricate LECs with various emission wavelengths, even the white emitting LECs. Red dye DCJTB was doped into MEH-PPV then a LEC device with a sandwich structure of ITO/MEH- PPV ＋ PEO ＋ LiCF3 SO3 ＋ DCJTB/A1 is fabricated. EL peak wavelength of the LEC devices ranges from 570 nm to 650 nm continuously, depending on the doping concentration of DCJTB. In the photoluminescence（PL） spectra excited with the excitation wavelength of MEH-PPV, it is observed that the emission from MEH-PPV decrease and DCJTB increase with the rise of the doped DCJTB mass concentration. This indicates that energy transfer occur from MEH-PPV to DCJTB. The redshift of DCJTB＇s emission caused by increasing its concentration is another factor for the phenomena.