电极材料对NPB/Alq_3有机电致发光器件性能的影响  

Influence of Electrode Materials on the Performance of NPB/Alq_3 Organic Electroluminescent Devices

作　　者：于军胜[1] 锁钒[1] 黎威志[1] 林慧[1] 李璐[1] 蒋亚东[1] 

机构地区：[1]电子科技大学光电信息学院电子薄膜与集成器件国家重点实验室,成都610054

出　　处：《物理化学学报》2007年第11期1821-1826,共6页Acta Physico-Chimica Sinica

基　　金：国家自然科学基金(60425101);教育部新世纪优秀人才计划(NCET-06-08125)和电子科技大学中青年学术带头人计划(060206)资助项目

摘　　要：采用不同材料作为有机电致发光器件(OELDs)的电极,制备了基本结构为[阳极/NPB(40 nm)]/Alq_3(50 nm)/阴极]的异质结双层器件,并通过改变OELDs器件的阴极或阳极来研究电极材料对器件光电性能的影响.研究结果表明,各器件电流-电压(Ⅰ-Ⅴ)关系的基本特征与陷阱电荷限制电流(TCLC)机制的拟合情况相符.由于有机材料本身能级的无序性以及载流子迁移率对温度和电场的依赖性,不同电极的载流子注入能力与其功函数并无直接关系.双层器件中由于空穴传输层的引入,使得载流子复合区域位于有机层异质结界面处,降低了金属阴极对激子的猝灭作用,从而大大提高了器件性能.此外,金属电极OLEDs器件结构具有的微腔效应会导致发射光谱的位移和谱峰宽度变窄,这表明通过对金属电极的表面改性和优化可使器件性能超过常规结构的器件.Double-layer heterojunction organic electroluminescent devices （OELDs） with a conventional structure of anodelN, N＇-bis-（3-naphthyl）-N, N＇-biphenyl-（1,1 ＇-biphenyl）-4,4＇-diamine [NPB （40 nm）]/tris-（8-hydroxyquinoline）- aluminum [Alq3（50 nm）]/cathode were fabricated using different materials as anode and cathode. The impact of electrode materials on device performance was studied by varying the electrodes of OELDs. The testing results of device electroluminescent characteristics showed that the current-voltage （Ⅰ-Ⅴ） relationship of the devices is in accordance with the theory of trapped charge limited current （TCLC） regime. Due to the disorder of organic material energy levels and the dependence of carrier mobility on temperature as well as electric field, charge carrier injection ability of different electrodes was not necessarily dependent on the work function of the electrodes. The introduction of hole transporting layer in double-layer devices enables the recombination zone of charge carriers to locate near the interface of organic heterojunction, which efficiently reduces the quenching effect of electrode on excitons, and thus largely enhances device performance. In addition, the microcavity effect in OELDs device with metallic electrode may lead to the shift of emissive spectra and the shrinkage of spectrum full width at half maximum. The results showed that enhanced device performance compared with conventional device can be anticipated by surface modification and optimization of metallic electrodes.

关 键 词：有机电致发光 电极材料 陷阱电荷限制电流 激子淬灭 器件性能 

分 类 号：TN383.1[电子电信—物理电子学]