中文摘要：

制备结构为ITO/Co/NPB/Alq3/LiF/Al的有机发光器件,测量了室温下磁场对器件发光效率和电流的影响.发现磁场强度小于80mT时,器件发光效率随磁场强度的增加而增大,最大为18.8%,随磁场强度的继续增加发光效率的增强趋于饱和.效率的增加是Co的自旋极化的注入和磁场效应共同作用的结果,其中自旋极化注入起主要作用.在磁场强度小于60mT时电流随磁场增强而增加,最大为6.9%,随磁场强度的进一步增加电流的增加有所减弱.产生这种现象的原因可归结为磁场相关的单线态极化子对的解离和三线态激子与自由载流子相互作用导致的结果.

英文摘要：

Efficiency and current measurements of ferromagnetic Co thin layer based organic light emitting diode,which has a structure of ITO/Co/NPB/Alq3/LiF/Al,are performed as a function of magnetic field at room temperature.The efficiency first increases by up to 18.8% as magnetic field increased to about 80 mT,and then appears to be almost saturated.The changes result from the spin-polaried injection of Co and the magnetic field effects（MFEs）,both of which increase the fraction of siglets among the total excitons,and the former is primary.The changing rate of current through the device is found to increase by up to 6.9% at about 60 mT,and then decrease slowly with magnetic field increasing.These observations are explained in terms of the MFEs of polaron pairs dissociation and magnetic-field dependence of tripletcharge reaction in excited states.