The transition from bipolaron to triplet-polaron magnetoresistance in a single layer organic semiconductor device
The transition from bipolaron to triplet-polaron magnetoresistance in a single layer organic semiconductor device
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DOI：
10.1016/j.orgel.2014.04.036
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发表时间：
2014-08
影响因子：
3.2
通讯作者：
Hang Gu;T. Kreouzis;W. Gillin
中科院分区：
文献类型：
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作者：
Hang Gu;T. Kreouzis;W. Gillin
我们测量了聚3-己基噻吩（P3 HT）基器件（Au/P3 HT（300 nm）/Al）在正向和反向偏压下的电流-电压-发光（I-V-L）和磁导率（MC）响应。在反向偏压（<1 V）下，负MC由单个非洛伦兹函数描述，与双极化子理论一致。在正向偏压下，当电流密度超过10−2A cm− 2时，从负饱和MC（低偏压）到正饱和MC（高偏压）的转变发生，并且与电致发光一致。在这些条件下，三重态密度（<$1015cm −3）变得与空穴密度（<$1016cm −3）相当，与三重态-极化子相互作用理论一致。从MC的电流密度的依赖性，我们得出结论，在正向偏置两种机制必须同时发生，在一个给定的设备，和MC的结果从两种机制之间的竞争的整体迹象。
We measure the current–voltage–luminescence (I–V–L) and Magneto-Conductance (MC) response of a poly(3-hexyl-thiophene) (P3HT) based device (Au/P3HT(300 nm)/Al) in forward and reverse bias. In reverse bias (<1 V), the negative MC is described by a single non-Lorentzian function, consistent with the bipolaron theory. In forward bias, the transition from negative saturation MC (low bias) to positive saturation MC (high bias) occurs when the current density exceeds ∼10−2A cm−2and coincides with electroluminescence. Under these conditions the triplet density (∼1015cm−3) becomes comparable to the hole density (∼1016cm−3), consistent with the triplet-polaron interaction theory. From the current density dependence of the MC we conclude that in forward bias both mechanisms must be occurring simultaneously, within a given device, and that the overall sign of the MC results from competition between the two mechanisms.