电化学方法在染料电致发光器件中的应用

Application of Voltammetry Method in Electroluminescence Cell

本文用电化学循环伏安法 (I V)、紫外光谱法 (UV)和荧光光谱法 (PL) ,比较了Alq、PBD和BBOT的紫外吸收谱图及I V曲线上的电化学行为。实验结果指出 ,Alq、PBD和BBOT的电化学行为均不可逆 ,均有大的阴极还原峰电流 ,表明它们是优良的电子传输体。从氧化还原峰的分析所得到的能带隙宽度的定性结果与UV图上的结果相一致。PL结果表明它们均具有良好的光致发光性能。

Thd contribution of electrochemistry method to the research of the electroluminescence cell has been discussed in this paper. In the electroluminescence cell electrons coming from metal electrode (such as Al, Mg) inject into the lowest unoccupied orbital (LUMO) and radioactively recombine with holes to generate electroluminescence. The energy transport can be calculated by electro chemistry method in the theory . The energy of LUMO and HOMO is corresponded to the potential of cathodic current peak and anodic current peak in the voltammogram chart,respectively.But the experiment results indicated that it is difficult to calculate the band gap energy accurately using electrochemistry method from I V voltammogram chart,because the electrode process in teh interface between the electrode and the solution is so complicated that much polar potential,such as double electronic layer polarization,concentration polarization need to be considered.In fact the I V voltammogram still give us many useful massages to explain the EL behaviors.The electrodic potentials in a redox reaction in dicate the attention ability for accepting or losing electrons in a electrochemistry reaction.A bigger I V area in the voltammogram will show a bigger charge or discharge quantity as a electron accepter or a electron donor.It is easy to find out most of organic polymers possessing conjugated double bonds appear a reversible redox characteristics such as polythiophene and 3 methyl poly thiophene. Ultra violet spectrograph and voltammograms of organic luminescent material,Alq,BBOT and PBD have been investigated in this paper.Results of I V cyclic voltammograms indicated Alq,BBOT and PBD apperas unreversible electrochemistry process with a big cathodic current peak,the cathodic reduction potential of PBD is more negative than that of Alq.Both of results of UV and voltammograms are in a good agreement with the electroluminescence behaviors.