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分别制备了荧光器件ITO/NPB/Alq3/LiF/Al和磷光器件ITO/NPB/CBP:Ir(ppy)3/BCP/Alq3/LiF/Al,测试了50mT磁场作用下器件的I-V和L-V特性.与零磁场相比荧光器件和磷光器件的效率分别增加了4.4%和7%.从有机电致发光的机制出发对该现象进行了解释,认为外加磁场可以使三重态激子发生塞曼分裂,进而在荧光器件中引起了三重态激子T+到单重态激子S的转化;磷光器件中增大了主体向客体的三重态能量传递速率.磁场作用下器件的电流也同时变大,对此认为是器件中的三重态激子与自由载流子的相互作用减弱,引起自由载流子的散射概率变小,迁移率变大的结果.
The IV and LV characteristics of the devices were tested under the conditions of 50mT magnetic field. The ITO / NPB / Alq3 / LiF / Al phosphors and the ITO / NPB / CBP: Ir (ppy) 3 / BCP / Alq3 / LiF / Al phosphors were prepared respectively. Compared with the zero magnetic field, the efficiency of the fluorescent device and the phosphorescent device increased by 4.4% and 7%, respectively.It is explained from the mechanism of organic electroluminescence that the applied magnetic field can cause the Zeeman splitting of the triplet exciton, Which in turn leads to the conversion of the triplet exciton T + to the singlet exciton S in the fluorescent device. The energy transfer rate of the triplet state of the host to the guest is increased in the phosphorescent device, and the current of the device under the magnetic field also increases. This is believed to be the result of the weakening of the interaction between the triplet excitons and the free carriers in the device, resulting in the reduction of the scattering probability of free carriers and the increase of the mobility.