有机发光器件的磁电导效应

制备了基于三(8-羟基喹啉)铝(tris-(8-hydroxyquinoline) aluminum (III), Alq₃) 的有机发光二极管, 并在不同偏压下测量了器件的室温磁电导效应.在小偏压下, 发光器件展示出明显的负磁电导效应.偏压增加后, 磁电导由负值变为正值, 出现了正负转变的现象. N, N'-二苯基-N, N'-(1-萘基)-1, 1'-联苯-4, 4'-二胺(N, N′-Di(naphthalen-1-yl)-N, N′ diphenyl-benzidine, NPB) 与铜酞菁 (Copper phthalocyanine, CuPc) 单极器件磁电导的测量结果表明, 发光器件在小偏压下的负磁电导效应来源于器件中的CuPc层. 双极电流的磁电导效应可用电子-空穴对模型进行解释, 而单极电流的磁电导效应可归因于器件中的极化子-双极化子转变. 在注入电流的变化过程中, 发光器件的正负磁电导转变是两种机理共同作用的结果.

Magnetoconductance effect in organic light-emitting devices

Organic light-emitting diode（OLED） based on tris-（8-hydroxyquinoline） aluminum（Ⅲ）（A1q₃） is fabricated,and its magnetoconductance （MC） effects are measured at different bias voltages.When the bias voltage is small,the OLED exhibits apparently a negative MC effect.After the bias voltage is increased,the MC value changes from negative to positive,displaying a negative-positive inversion. The MC effects in N、A’-Di（naphthalen-l-yl）-A、N’ diphenyl-benzidine（NPB） and Copper phthalocyanine（CuPc） unipolar devices show that the negative MC effect in OLED comes from the CuPc layer in device.The MC effect of bipolar current can be explained using the electron-hole pair model.The MC effect of unipolar current can be attributed to the polaron-bipolaron transition in device. The positive-negative MC inversion in OLED results from the simultaneous contributions of the above two mechanisms during the variation of the injection current.