电场诱导空穴注入缓冲层PEDOT∶PSS取向对OLED发光性能的影响  

High-electric-field Treated PEDOT∶PSS as Hole Injecting Buffer Layer for Polymer Light-emitting Diodes

作　　者：秦丽芳[1] 侯延冰[1] 师全民[1] 蒋婧思[1] 高瑞[1] 王琰[1] 

机构地区：[1]北京交通大学光电子技术研究所,北京100044

出　　处：《发光学报》2008年第1期41-45,共5页Chinese Journal of Luminescence

基　　金：教育部跨世纪人才基金;教育部重点项目(105041);国家自然科学基金(90401006;10434030;90301004);"973"计划(2003CB314707);华南理工大学特种功能材料及其制备新技术教育部重点实验室资助项目

摘　　要：实验中以PEDOT∶PSS在ITO基片上旋涂作为空穴传输层,并且在旋涂PEDOT∶PSS的过程中在与ITO玻璃平面垂直的方向施加一个诱导聚合物取向的高压电场,试验着重研究了所加电场强度对双层器件:ITO/PEDOT∶PSS/MEH-PPV/Al器件性能的影响。测试结果表明,旋涂时所加电场的大小对器件的发光强度和起亮电压都有明显的影响。随着所加电场的增大,器件发光强度明显增加,起亮电压减小。由此表明:在高电场作用下,聚合物分子链沿电场方向发生了取向,而且随着电场增强这种取向作用会表现得越明显,并且在PEDOT∶PSS膜表层会形成一个梯度变化的PSS聚集,使得从ITO到MEH-PPV的功函数逐渐上升,降低空穴注入势垒,增强了空穴的注入效率。A organic light-emitting diode device with a structure of ITO/PEDOT： PSS/MEH-PPV/Al was fabricated. High electric field is applied vertically to the surface of the sample to polarize the PEDOT： PSS layer during the process of spin-coating. Due to the electric-field induced orientation of the PEDOT： PSS,the device with an appropriately treated PEDOT： PSS film as hole-injecting buffer layer exhibited significantly enhanced luminescence and decreased driving voltage. The results suggest that the electric field-induced orientation is useful for the improvement of device performance. And the polarized MEH-PPV layer exhibits a low resistance compared to the unpolarized layer. By looking at the PEDOT： PSS fabrication steps, it can be inferred that a gradient enrichment of negative PSS content can form at the top surface due to the attractive power of the external electric-field. This should aid charge injection into the MEN-PPV by gradually increasing the work function from the ITO surface to the MEN-PPV surface giving a graduated barrier to hole-injection.

关 键 词：分子取向 电致发光 空穴注入 

分 类 号：TN383.1[电子电信—物理电子学] TN873.3