不同BCP插层厚度及工作温度对高场有机磁电导正负转变的影响  

Influence of BCP inserted-layer and working temperature on the sign inversion of magneto-conductance at high magnetic field in organic light-emitting diodes

作　　者：陈林[1] 张巧明[1] 贾伟尧[1] 焦威[1] 刘亚莉[1] 游胤涛[2] 熊祖洪[1] 

机构地区：[1]西南大学物理科学与技术学院,发光与实时分析教育部重点实验室,重庆400715 [2]复旦大学应用表面物理国家重点实验室,上海200433

出　　处：《科学通报》2013年第9期803-809,共7页Chinese Science Bulletin

基　　金：重庆市科委自然科学基金(2010BA6002);复旦大学应用表面物理国家重点实验室开放基金(KL2011_06);国家自然科学基金(10974157)资助

摘　　要：采用插入较厚(40,80和120nm)的BCP空穴阻挡层,制备了结构为ITO/CuPc/NPB/Alq3/BCP(xnm)/Al的有机发光二极管,并在不同温度下测量了器件电流随外加磁场的变化(即magneto-conductance,MC).发现不同厚度BCP插层器件在低场(0B50mT)下均表现为正磁电导效应,且这一特性与器件工作温度无关.但高场部分(B>50mT)的MC却表现出对温度及厚度有较强的依赖关系,即随着温度的降低,120nmBCP插层器件表现出明显的正负磁电导转变;而80和40nm的BCP器件则不存在这种转变现象,在低温下只存在负磁电导成分.其原因可能是:MC低场正磁电导部分由超精细相互作用引起;而高场MC的正负转变则主要是由于较厚BCP插层引起大量没有复合的剩余空穴,与低温下长寿命的三重态激子相互作用(即TQA作用)引起的.Organic light-emitting diodes with structure of 1TO/CuPc/NPB/Alq3/BCP（x）/A1 were fabricated in this work. The thickness of BCP is 40, 80 and 120 nm, respectively. The magnetic field effects on the conductance （magneto-conductance, MC） of these diodes were measured at temperature range from 300 to 15 K, respectively. Results show that the MC responses of all the three devices reveal a positive component under low magnetic field at all working temperatures. However, the MC effects under high magnetic field of the BCP（x）-inserted devices show a strong dependence on the temperature and device thickness. In particular, the MC of BCP （120 nm） device shows a sign inversion as decreasing the temperature. However, this phenomenon can not be observed in the BCP （40, 80 nm） devices. Only negative component of MC is existed in the two devices at low temperatures. We suggest that the positive MC in low magnetic field is caused by hyperfine interaction. Moreover, the sign inversion of MC at high magnetic field is caused by the interaction between the triplet excition with long lifetime at low temperature and holes which are intercalated by the BCP inserted layer.

关 键 词：有机磁电导 高场正负转变 空穴阻挡层 三重态激子-电荷 相互作用 

分 类 号：TN383.1[电子电信—物理电子学]