室温下磁场对基于Alq3的有机电致发光器件的影响

制备了ITO/NPB/LiF/Alq₃/LiF/Al的器件，测量了该组器件效率和亮度的磁效应.结果表明，在50 mT磁场中，当LiF缓冲层厚度为0.8 nm时，器件的效率最大增加了12.4%，磁致亮度最大变化率17%.同时，制备的磷光器件ITO/NPB/LiF/CBP:6 wt% Ir(ppy)₃/BCP/Alq₃/ LiF/Al，在50mT磁场作用下，当LiF缓冲层的厚度为0.8 nm时，器件的效率最大增加12.1%.在Alq_{3 关键词： 有机发光 磁场 效率 磁致亮度}

The role of magnetic fields on organic light-emitting devices based on aluminum tris(8-hydroxyquinoline)(Alq3) at room temperature

We report the magnetic-field effect (MFE) in Alq₃ based organic light-emitting device (OLED) with the structure of ITO/NPB/LiF/Alq₃/LiF/Al.When an external magnetic field of 50 mT and insertion of LiF thickness of 0.8 nm is applied, the current efficiency and the brightness of the device increase to 12.4% and 17%, respectively.The origin of the improvements could be attributed to the Zeeman effect,which reduces the hyperfine interactions of electrons and holes, inhibiting energy transfer from the singlet polaron pairs to triplet polaron pairs and increasing the population of singlets.Similar MFE was observed in phosphorescent organic light-emitting diodes(PhOLEDs).The current efficiency of ITO/NPB/LiF(0.8 nm)/CBP:6 wt% Ir(ppy)₃/BCP/Alq₃/LiF/Al increases to 12.1% at 50 mT.Magnetic-field-induced increase of singlet excitons in the CBP matrix reflects increase of triplet excitons in the dispersed Ir(ppy)₃ molecules in the CBP+Ir(ppy)₃ blend.