Spin dynamic study on the electric field dependence of carrier generation.
Spin dynamic study on the electric field dependence of carrier generation.
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DOI：
10.1021/jp044475e
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发表时间：
2005-03
期刊：
影响因子：
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通讯作者：
Fuyuki Ito;T. Ikoma;K. Akiyama;S. Tero-Kubota
中科院分区：
文献类型：
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作者：
Fuyuki Ito;T. Ikoma;K. Akiyama;S. Tero-Kubota
利用掺杂受主的聚N-乙烯基咔唑薄膜，测量了不同电场下磁场对光生电荷产生效率的影响，以阐明电场对光电导聚合物分子固体中光生载流子产生基元过程的影响.外加磁场在几个纳米尺度内影响了电子-空穴对之间的电子自旋动力学，降低了光生载流子的产生效率。观察到的MFE由于超精细机制几乎是独立的电场。通过采用基于一维晶格模型的随机Liouville方程，我们进行了一些模型计算的解离，跳跃，和重组率的MFE的产生效率的依赖性。从观察到的和计算的MFE之间的比较，得出的结论是，电场的影响的解离比跳跃和重组。这与迄今为止用于分析载流子产生效率的电场依赖性的Onsager模型中的概念一致。一维晶格模型是一种适用于高分子固体中载流子生成的模型，除了空穴的长程跳跃外，它与Onsager模型在性质上是一致的。
Using an acceptor-doped poly(N-vinylcarbazole) film, the magnetic field effect (MFE) on the generation efficiency of photoinduced charge was measured under various electric fields in order to clarify how the applied electric field affects the elementary processes in the photocarrier generation in photoconductive polymeric molecular solids. The external magnetic field influenced the electron spin dynamics among the geminate electron-hole pairs within a scale of a few nanometers and decreased the photocarrier generation efficiency. The observed MFE due to a hyperfine mechanism was almost independent of the electric field. By employing the stochastic Liouville equations based on a one-dimensional lattice model, we performed some model calculations for the dissociation, hopping, and recombination rate dependence of MFE on the generation efficiency. From a comparison between the observed and calculated MFE, it was concluded that the electric field affects the dissociation more than the hopping and the recombination. This coincides with the concepts in the Onsager model that is used to analyze the electric field dependence of carrier generation efficiency so far. The one-dimensional lattice model is a proper model for the carrier generation in polymeric molecular solids, which is qualitatively consistent with the Onsager model except for the long-range hole jump.