绝缘层LiF/Al电极对提高P-PPV发光器件发光性能的研究  

Performance Improvement of PPPV Light-emitting Diodes with Metal Fluoride Cathode

作　　者：林海波[1] 徐晓轩[1] 吴宏滨[2] 王斌[1] 俞钢[1] 张存洲[1] 

机构地区：[1]南开大学泰达应用物理学院,天津300457 [2]华南理工大学材料学院高分子光电材料及器件研究所,广东广州510640

出　　处：《发光学报》2005年第4期469-472,共4页Chinese Journal of Luminescence

基　　金：国家教育部"振兴"计划资助项目(A01504)

摘　　要：为了提高聚合物电致发光器件中Ba(Ca)/A l阴极的稳定性,在该阴极与聚合物发光材料poly(2-(4-ethylexyl)phenyl-1,4-phenylene vinylene)(P-PPV)层之间插入一层7 nm的L iF绝缘层,发光器件的发光性能在多项参数(发光器件的电压-电流特性、发光强度及外量子效率,以及电流效率等发光性能指标)上能够与工作性能优良但稳定性较差的Ba(Ca)/A l电极结构PLED s器件的发光特性具有可比性。这对于研制高效率、高稳定的聚合物电致发光器件并最终将其用于商业目的,具有重大现实意义。The electronic and optical performances of P-PPV light-emitting diodes with lithium fluoride insulating layer between the metal cathode and active polymer are studied. As for the polymer light-emitting diodes, optimization of charge injection lies in the dominant factors for substantive improvement performance. Since the minority carriers dominate the recombination thus the radiation, their injection takes priority over that of majority carriers. Generally in semiconducting polymers, holes are majority carriers while electrons are the minority, the carrier misbalance between electrons and holes further deteriorate in the fact that holes usually take possession of higher mobility and smaller injection barrier. To balance injection charge carriers and facilitate the electron injection, there are two commonly stratagems to be used in cathode fabrication. One is to employ low work function metals such as barium and calcium as cathode though they are susceptible to degradation upon water vapor and oxygen. The other choice is proposed to insert an insulating thin layer of lithium fluoride between polymer/electrode interfaces to build a bilayer cathode. As shown by the experiment results, the LiF/ Al double-layer-cathode with Ba（ Ca）/Al electrode devices can improve in luminescence performance. Band bending and injection potential decrease of minority carrier caused by the inlay of metal fluoride insulating layer, which is proposed to be responsible for the enhanced electron injection and improved performance in polymer light emitting diodes.

关 键 词：聚合物发光二极管 P-PPV LIF 金属-半导体界面 

分 类 号：TN381.1[电子电信—物理电子学] TN873.3