Stochastic approach to hopping transport in disordered organic materials
Stochastic approach to hopping transport in disordered organic materials
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无序有机材料中跳跃传输的随机方法
DOI：
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发表时间：
2004
期刊：
影响因子：
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通讯作者：
G. Adriaenssens
中科院分区：
文献类型：
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作者：
E. Emelianova;G. Adriaenssens
与无机非晶半导体不同的是，无序有机物中的所有电子态都是局域化的，导电可以在这些态的流形中通过载流子跳跃来进行，因此，这些态通常被称为跳跃位点。描述此类系统中电荷输运的最常用方法之一是变程跳变理论。虽然这一理论的一般原理已经为人所知并接受了多年，但这一理论的许多重要方面和应用直到最近才得到研究。在这个调查中，我们讨论了一些方面的跳跃在无序有机材料，没有收到太多的关注，在过去。在对平衡迁移率计算的一般概述之后，展示了有效输运能量的概念如何有效地减少了对跳跃的描述，这是一个更简单的陷阱控制能带输运问题。详细讨论了高载流子密度和缺陷中心对载流子迁移率的影响，以及空间电荷限制电流的特殊情况。在随后的章节中，将考虑掺杂对态密度分布和输运特性的影响。极化子形成和深俘获对无序有机材料中载流子迁移活化能的影响是我们最后一节的主题。
At variance with inorganic amorphous semiconductors, all electronic states in disordered organics are localized and electrical conduction can proceed by carrier hopping within the manifold of those states that are, therefore, often referred to as hopping sites. One of the most common approach to the description of charge transport in such systems is the variable-range hopping theory. While the general principles of this theory have been known and accepted for years, many important aspects and applications of this theory have only been examined more recently. In this survey we discuss a number of facets of hopping in disordered organic materials that have not received much attention in the past. Following a general outline of the calculation of the equilibrium mobility it is shown how the concept of an effective transport energy effectively reduces the description of hopping a much simpler problem of trap-controlled band transport. The influence of high carrier densities and of defect centers on the carrier mobility as well as the special case of space charge limited currents are discussed in detail. In subsequent sections, the effect of doping on the density-of-states distribution and on transport characteristics are considered. The effect of polaron formation and deep trapping on the activation energy of the carrier mobility in disordered organic materials are the subject of our final section.