LiF插层对有机发光二极管磁场效应的调控  

Tuning effect of magnetic-field in organic light emitting diodes using LiF layer

作　　者：刘荣[1] 张勇[1] 雷衍连[1] 陈平[1] 张巧明[1] 熊祖洪[1] 

机构地区：[1]西南大学物理科学与技术学院,重庆400715

出　　处：《物理学报》2010年第6期4283-4289,共7页Acta Physica Sinica

基　　金：教育部留学回国人员科研启动基金(批准号:20071108);国家自然科学基金(批准号:10974157);霍英东教育基金会高等院校青年教师基金(批准号:101006)资助的课题~~

摘　　要：制备了有LiF插层的有机发光二极管,以八羟基喹啉铝(Alq3)作为电子传输层,N,N′-二苯基-N,N′-二(1-萘基)-1,1′-联苯-4,4′-二胺(NPB)作为空穴传输层.通过改变Alq3与NPB间LiF插层的厚度,研究了不同温度下器件的光电特性及电致发光的磁场效应.测量结果表明:LiF插层可以影响器件内部载流子的输运和激发态的形成.较厚的插层阻碍了空穴的传输,使器件的电流效率变低.但实验中发现,LiF插层可实现对器件电致发光磁场效应的有效调控.与常规器件相比,各温度下含插层器件的磁场效应在小磁场范围内(磁感应强度B<40mT)均得到增强;低温情况下,插层结构使发光强度在较大磁场范围内(B≥40mT)的下降趋势大大减弱,且插层厚度越大,该下降趋势就越不明显.这些实验结果间接说明了三重态激子的浓度可以影响电致发光的磁场效应.The organic light emitting diode with inserted LiF layer has been fabricated. Tris-（8-hydroxyquinoline） aluminum （Alq3） was used as electron-transport layer and N,N′-bis（1-naphthyl）-1,1′-biphenyl-4,4′-diamine （NPB） was used as hole-transport layer. By changing the thickness of LiF deposited between Alq3 and NPB,the optoelectrical properties and the magnetic field effect on electroluminescence were studied at different temperatures. The measurement results show that using LiF layer enables the transport of carrier and the formation of excited states inside the device. A thick LiF layer blocks the transport of holes,lowering the efficiency of the device. However,use of LiF layer can effectively tune the magnetic field effect of electroluminescence. Compared with conventional devices,the magnetic field effect of device with inserted LiF layer was strengthened within low-field range （the magnetic induction B 40 mT） at different temperatures. At low temperatures,inserting LiF layer significantly weakens the magnitude of high-field （ B ≥40 mT） decrease of electroluminescence,and the thicker the LiF layer,the smaller the magnitude of decrease. These observations indicate that the concentration of the triplet excitons offects the high magnetic field decrease of electroluminescence at low temperatures.

关 键 词：LiF插层结构 磁场效应 三重态激子 

分 类 号：TN312.8[电子电信—物理电子学]