Alq_3有机发光二极管中的超小磁场效应

Ultrasmall magnetic field effects in Alq_3-based organic light-emitting diode

制备了基于Alq3的有机发光二极管,器件结构为ITO/NPB/Alq3/LiF/Al,并在不同温度测量了器件在不同偏压下传导电流与电致发光的磁场效应.在较大的磁场范围内,磁电导曲线基本服从B2/(|B|+B0)2规律.而在零场附近很小的磁场范围内,测量结果显示出奇特的超小磁场效应.考虑载流子自旋与有机分子中核自旋之间的超精细相互作用对载流子自旋的调控,可以对这种零场附近的超小磁场效应给出合理解释.

Organic light-emitting diode（OLED） based on Alq3 has been fabricated.The structure of devices is ITO/NPB/Alq3/LiF/Al.The magnetic field effects on current and electroluminescence were measured with constant voltage bias at different temperatures.Within the large range of magnetic field,the magnetoconductance curves follow the rules of B2/（｜B｜＋B0）2.While in a very small range around zero-field,the measurement results exhibit a strange ultrasmall magnetic-field effect.Such an ultrasmall magnetic-field effect around zero-field can be explained by considering the tuning effect on the carrier＇s spin due to the hyperfine interaction between the spin of carrier and the spin of nuclear in organic molecule.