Two-dimensional charge transport in self-organized, high-mobility conjugated polymers
Two-dimensional charge transport in self-organized, high-mobility conjugated polymers
复制标题
DOI：
10.1038/44359
复制
发表时间：
1999-10-14
期刊：
影响因子：
64.8
通讯作者：
de Leeuw, DM
中科院分区：
文献类型：
--
作者：
Sirringhaus, H;Brown, PJ;de Leeuw, DM
在许多溶液处理的半导体共轭聚合物中的自组织导致复杂的微结构，其中有序的微晶域嵌入在无定形基质中（I）。这对这些材料的电学性质有重要影响：电荷传输通常受到最困难的跳跃过程的限制，因此由无序基质主导，导致低电荷载流子迁移率（2）（小于或等于10（-5）cm（2）V（-1）s（-1））。在这里，我们使用薄膜，场效应晶体管结构，以探测在共轭聚合物聚（3-hexylthiophene），P3 HT的有序微晶域的输运性质，在P3 HT的自组织结果在一个片层结构与二维共轭片层形成的链间堆叠。我们发现，根据加工条件，薄层可以采用两种不同的取向-平行和垂直于衬底-其迁移率相差超过100倍，并可以达到高达0.1 cm（2）V-1 s（-1）的值（参考文献3，4）。场致电荷的光谱，结合迁移率各向异性，揭示了二维链间字符的极化电荷载流子，表现出较低的弛豫能比孤立的一维链上的相应的自由基阳离子。通过自组织共轭层中的二维输运实现高迁移率的可能性对于聚合物晶体管在逻辑电路（5）和有源矩阵显示器（4，6）中的应用是重要的。
Self-organization in many solution-processed, semiconducting conjugated polymers results in complex microstructures, in which ordered microcrystalline domains are embedded in an amorphous matrix(I). This has important consequences for electrical properties of these materials: charge transport is usually limited by the most difficult hopping processes and is therefore dominated by the disordered matrix, resulting in low charge-carrier mobilities(2) (less than or equal to 10(-5) cm(2)V(-1)s(-1)). Here we use thin-film, field-effect transistor structures to probe the transport properties of the ordered microcrystalline domains in the conjugated polymer poly(3-hexylthiophene), P3HT, Self-organization in P3HT results in a lamella structure with two-dimensional conjugated sheets formed by interchain stacking. We find that, depending on processing conditions, the lamellae can adopt two different orientations-parallel and normal to the substrate-the mobilities of which differ by more than a factor of 100, and can reach values as high as 0.1 cm(2) V-1 s(-1) (refs 3, 4). Optical spectroscopy of the field-induced charge, combined with the mobility anisotropy, reveals the two-dimensional interchain character of the polaronic charge carriers, which exhibit lower relaxation energies than the corresponding radical cations on isolated one-dimensional chains. The possibility of achieving high mobilities via two-dimensional transport in self-organized conjugated lamellae is important for applications of polymer transistors in logic circuits(5) and active-matrix displays(4,6).