未掺杂条件下载流子平衡提高有机电致发光器件效率的研究  

The Research on the Efficiency Improvement of Undoped Organic Light-emitting Devices by Charge Balance

作　　者：徐维[1] 徐贵[2] 曹杰[3] 

机构地区：[1]五邑大学数学物理系,江门529020 [2]包头供电局修试管理处,包头014030 [3]五邑大学图书馆,江门529020

出　　处：《长春理工大学学报（自然科学版）》2009年第4期560-564,共5页Journal of Changchun University of Science and Technology(Natural Science Edition)

基　　金：国家自然科学基金(90201034;60477014;60577041);国家973计划项目(2002CB613400)

摘　　要：用具有高电子迁移率(5×104cm2V1s1)的材料4,7-diphenyl-1,10-phenanthroline(BPhen)作为电子传输层(ETL),N,N-bis-[1-naphthy(-N,Ndiphenyl-1,1'-biphenyl-4,4'-diamine)](NPB)作空穴传输层(HTL),tris(8-hy-droxyquinoline)aluminum(Alq3)作发光层(EML),使有机薄膜电致发光器件的效率得到显著改善。器件基本结构为:ITO/NPB/Alq3/BPhen/LiF/Al。通过对HTL和ETL的厚度进行优化,在电流密度为20mA/cm2时,器件的电流效率达到6.80cd/A,亮度达到1361cd/m2。为了探索发光器件的效率得以改善的原因,制备了结构为ITO/Alq3/BPhen/Al的electron-only器件和结构为ITO/NPB/Al的hole-only器件。通过调整hole-only器件中空穴传输层(HTL)和electron-only器件中电子传输层(ETL)之间的厚度匹配并比较它们之间的J-V曲线,发现当电子和空穴达到载流子平衡时,发光器件获得最佳效率和亮度。According to the principle of carrier balance,the study is focused on two aspects：one is the thickness adjustment of organic layers,another is the improvement of transport layer.At last,the effective carrier control is achieved and the performance of devices is enhanced.In the thickness adjustment of organic layers,efficiency enhancement in organic light em-itting diodes（OLEDs）was achieved by introducing 4,7-diphenyl-1,10-phenanthroline（BPhen）as the electron transport layer（ETL）on account of its high electron mobility of 5×10^4cm^2V^-1s^-1, using N,N-bis-[ 1-naphthy （-N, N diphenyl-1,1＇-biphenyl-4, 4＇-diamine）] （NPB） as hole transport layer （HTL） and tris （8- hydroxyquinoline） aluminum （Alq3） as emission layer （EML）. The basic structure of the devices is ITO/NPB / Alq3 / BPhen/LiF / Al. After the thicknesses of HTL and ETL were optimized, the most efficient device with the luminous efficiency of 6.80 cd/A and the luminance of 1361 cd/m^2 was obtained at a current density of 20 mA/cm^2. We also fabricated electron-only devices with the structure oflTO/Alq3 / BPhen / Al and hole-only devices with the structure oflTO/NPB/Al to investigate the reason for the efficiency enhancement in complete devices. By comparing the J-V characteristics of hole-only and electron-only devices, it has been found that there is a highly efficient balance between holes and electrons for particular thicknesses of NPB and BPhen in our devices. This efficient carrier balance leads to high luminous efficiency and brightness.

关 键 词：载流子平衡 厚度优化 发光效率 

分 类 号：TN383[电子电信—物理电子学]