利用有机磁电导分析Rubrene发光器件中三重态激子解离和电子散射过程  

Analysis of triplet dissociation and electron scattering in the Rubrene-based devices by utilizing magneto-conductance

作　　者：陈颖冰[1] 袁德[1] 向杰[1] 陈秋松[1] 贾伟尧[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：《中国科学：技术科学》2016年第1期61-67,共7页Scientia Sinica(Technologica)

基　　金：国家自然科学基金(批准号:11374242;11404266)资助项目

摘　　要：为了研究红荧烯（5,6,11,12-tetraphenylnaphthacene,Rubrene）器件中三重态激子与电荷相互作用的微观过程,制备了基于Rubrene的有机发光二极管,并测量了室温下器件的磁电导（magneto-conductance,MC）.实验发现,器件MC曲线的幅值非常小且表现出了奇特的变化：即在0-8 m T的磁场范围内,MC随磁场快速增大;当磁场处于8-100 m T时,MC则表现为下降;但当磁场大于100 m T时,MC则表现为缓慢增加.分析发现,Rubrene器件中除了超精细相互作用外,还有空穴对三重态激子的解离作用和三重态激子对电子的散射作用的共存,且它们都受单重态激子分裂（singlet fission）的影响.利用Lorentzian和non-Lorentzian经验函数可以对MC进行较好拟合,进一步证实了上述观点.三重态激子解离和电子散射共存这一发现不仅有助于对Rubrene器件中电荷与激发态间相互作用机制的认识,在优化器件性能方面也有一定的指导意义.The organic light-emitting diodes（OLEDs） based on 5,6,11,12-tetraphenylnaphthacene（Rubrene） have been fabricated to investigate the microscopic evolution of triplet-charge interaction in this work. The magneto-conductance（MC） of the devices has been measured at room temperature. The MC curves possess a very small magnitude and peculiar line-shape compared to those from the reference samples. Specifically, the MC magnitude is around 0.1%, and the MCs sharply increase in low field（≤8 mT） and reach a maximum, then decrease in medium field（8≤B≤100 m T） and reach a minimum, and then rise slowly while the field strength is larger than 100 m T. By fitting the MC curves with the combination of one Lorentzian and two non-Lorentzian empirical equations, three mechanisms which are all influenced by singlet fission are proposed. They are hyperfine interaction, the dissociation process of the triplet excitons with holes, the scattering process of electron by the triplet excitons. This study is helpful for understanding the microscopic process of the interaction between triplet excitons and charges and improving the performance of organic optoelectronic devices.

关 键 词：红荧烯分子 磁电导 三重态激子-电荷作用 单重态激子分裂 

分 类 号：TN312.8[电子电信—物理电子学]