摘要
制备了常规有机发光二极管ITO/NPD/Alq3/LiF/Al,测量了该器件发光的磁场效应.发现尽管在1T范围内的磁场对发光层Alq3的光致发光没有影响,但磁场作用下器件的电致发光(MEL)却呈现出明显的磁效应,且MEL与器件的偏压有很强的依赖关系:在小偏压时,随着磁场的增加MEL是单调递增,且在大小约为40kA/m的磁场下达到饱和,之后即使磁场增大到约1T的情况下也没有变化;但当偏压变大时,MEL则呈现先增加,在40kA/m处达到峰值后却又减弱,而且偏压越大该MEL的减弱则越明显.对所观察到的实验结果进行了定形解释,即三线态激子相互淬灭产生单线态激子和三线态激子与器件中的非平衡载流子相互作用是此效应的物理机理.
A conventional organic light emitting diode, which has a structure of ITO/NPD/Alq3/LiF/Al, was fabricated and the magnetic field effects（MFEs） on its electroluminescence（EL） were measured. We found that the MFEs of the organic EL is strongly dependent on the applied bias on the device while the photoluminescence from the Alq3 film within the device is independent of the magnetic field. At low bias, the MFEs first rapidly increase with the magnetic field and then saturate at about 40 kA/m, however at high bias the MFEs will decrease after this saturation, and the larger the bias, the stronger the decrease. The mutual annihilation of triplet-triplet pairs producing excited singlet excitons and the interaction between triplet excitons and excess carriers of Alq3 anion or cation are the physical mechanisms of the phenomena observed in this study.
出处
《物理学报》
SCIE
EI
CAS
CSCD
北大核心
2007年第5期2979-2985,共7页
Acta Physica Sinica
基金
国家自然科学基金(批准号:10504027)
教育部"新世纪优秀人才支持计划"(批准号:NCET-05-0772)
霍英东教育基金会(批准号:101006)
人事部留学人员科技活动项目
重庆市自然科学基金(批准号:CSTC
2005BB3049)资助的课题~~
关键词
有机发光
磁场效应
激子淬灭
organic electroluminescence, magnetic field effects, exciton annihilation
