以聚乙烯亚胺作为电子注入层的聚合物发光器件特性研究  

Polymer LED using ethoxylated polyethylenimine as electron injection layer

作　　者：王瑞雪[1] 范昌君 杨晓晖[1] 

机构地区：[1]西南大学物理科学与技术学院,重庆400715

出　　处：《光电子．激光》2015年第4期649-654,共6页Journal of Optoelectronics·Laser

基　　金：国家自然科学基金(61177030;11474232);教育部新世纪优秀人才(NCET-11-0705);西南大学博士基金(SWU111057)资助项目

摘　　要：在传统结构与倒置结构的有机发光二极管(LED)的聚合物发光层和阴极之间加入聚乙烯亚胺(PEIE)层能够显著地提高器件的发光效率。通过采用不同厚度的PEIE层的器件发光特性研究表明:PEIE层作为电子注入层(EIL)/空穴阻挡层(HBL)来平衡器件中的电子和空穴浓度,这主要来源于PEIE作为界面偶极层,能有效地降低阴极与发光层之间的电子注入势垒。To improve luminance efficiency of conventional and inverted light emitting devices, we imple- ment an ethoxylated polyethylenimine （PEIE） layer between light emitting polymer and cathode. Studies on characterizations of light emitting devices with various PEIE layer thicknesses reveal that ethoxylated polyethylenimine layer mainly works as an electron injection/hole blocking layer. Conventional and in- verted light emitting devices using a PEIE electron injection layer show comparable luminance efficiency to the analogous devices with a CsF or with a ZnO/PEIE electron injection layer. Analyses of current density-voltage characteristics of single-electron devices manifest that PEIE layer enhances electron in- jection efficiency by a factor of 5-10. Results of X-ray photoelectron-spectroscopy （XPS） measurements indicate that PEIE layer reduces the Work function of A1 by ca. 1 eV,thus significantly decreasing the e- lectron injection barrier, which can be attributed to the intrinsic dipole moment of PEIE or the formation of interfacial dipoles. Apart from excellent electron injection/hole blocking properties, PEIE is air-stable and more compatible with the neighboring organic layer than metal fluorides, which can be processed from aqueous or alcohol solution under ambient conditions. Thus, PEIE serves as a promising electron in- jector in organic electron devices and is particularly suitable for construction of multilayer devices with versatile and enhanced properties.

关 键 词：聚合物发光二极管(PLED) 传统结构 倒置结构 聚乙烯亚胺(PEIE) 电子注入层(EIL) 

分 类 号：TN383.1[电子电信—物理电子学]