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通过在器件复合发光区附近插入空穴阻挡层BCP,制备了一种具有非平衡传输性能的荧光染料掺杂型发光二极管,其结构为ITO/CuPc/NPB/NPB:DCM(5wt%)/BCP/Alq3/LiF/Al,并在不同温度和电压下测量了器件的注入电流随外加磁场的变化(即磁电导效应).实验结果表现为:当磁场处在0～40mT时,该非平衡发光器件的磁电导随磁场的增加而迅速增大(即表现为快变的正磁电导效应).这一实验现象与具有相对平衡传输性能的发光器件中所观测到的磁电导效应一致;当磁场大于40mT时,非平衡发光器件的磁电导随磁场的进一步增加表现为缓慢下降(即缓变的负磁电导效应成分),而平衡器件的磁电导则变为继续缓慢增加(即为缓变的正磁电导效应).本文对非平衡传输掺杂型发光器件的体系特征进行了讨论,并基于三重态激子-电荷(T-Q)反应受外加磁场的影响对上述实验现象进行了定性解释.
By inserting a hole-blocking layer (BCP) near the recombination light-emitting area of the device, a fluorescent dye-doped light emitting diode with unbalanced transmission performance was prepared and its structure was ITO / CuPc / NPB / NPB: DCM / Alq3 / LiF / Al, and the change of the device’s injection current with the applied magnetic field (ie, the magneto-conductance effect) was measured at different temperatures and voltages.The experimental results show that when the magnetic field is between 0 and 40mT, the unbalanced luminescence The magnetic conductance of the device rapidly increases with the increase of the magnetic field (ie, exhibits a fast changing positive magnetic conductance effect.) This experimental phenomenon is consistent with the observed magneto-conductance effect in a light-emitting device with relatively balanced transmission performance. Above 40 mT, the magnetic conductance of the unbalanced light emitting device shows a slow decrease (ie, a slowing negative magnetic conductance component) as the magnetic field increases further, while the magnetic conductance of the balanced device continues to increase slowly (ie, slow Positive magneto-conductance effect.) The system characteristics of the non-equilibrium transmission doping type light-emitting device are discussed in this paper, and the above experimental phenomena are qualitatively explained based on the influence of external magnetic field on the triplet exciton-charge (TQ) reaction.