机构地区: 吉林师范大学信息技术学院
出 处: 《物理学报》 2010年第5期3571-3576,共6页
摘 要: 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50mT磁场中,当LiF缓冲层厚度为0.8nm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:6wt%Ir(ppy)3/BCP/Alq3/LiF/Al,在50mT磁场作用下,当LiF缓冲层的厚度为0.8nm时,器件的效率最大增加12.1%.在Alq3的荧光器件中,由于发光材料在磁场的作用下产生了塞曼效应,超精细耦合作用减弱,单重态的极化子对向三重态的极化子对的转移受到了抑制,从而使单重态激子的数量增加,发光增强;与荧光器件类似,在Ir(ppy)3的磷光器件中,效率增加的原因是由于荧光主体材料CBP在磁场的作用下单重态激子数量增加,而间接的导致了磷光材料系间窜越现象的加剧所引起的. 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.
领 域: [电子电信]