Surface-Directed Molecular Assembly of Pentacene on Monolayer Graphene for High-Performance Organic Transistors
Surface-Directed Molecular Assembly of Pentacene on Monolayer Graphene for High-Performance Organic Transistors
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DOI：
10.1021/ja1097463
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发表时间：
2011-03-30
影响因子：
15
通讯作者：
Cho, Kilwon
中科院分区：
文献类型：
--
作者：
Lee, Wi Hyoung;Park, Jaesung;Cho, Kilwon
由于石墨烯被认为是一种理想的候选电极材料，使用石墨烯电极的有机电子器件受到了极大的关注。在制造图案化石墨烯电极的过程中，转移和光刻过程通常会在石墨烯表面留下聚合物残留物。然而，这些残基对有机半导体在石墨烯表面生长机理的影响尚未见报道。在这里，我们证明了留在石墨烯表面的聚合物残基诱导并五苯的直立取向，从而控制并五苯的生长，使得分子组装对于电荷传输是最佳的。因此，使用含有聚合物残基的源漏单层石墨烯电极的并五烯场效应管(FET)显示出1.2cm2/V S的高场效应迁移率。相反，具有平躺结构的分子组装的并五烯的外延生长是由于没有聚合物残基的清洁的石墨烯电极之间的pi-pi相互作用促进的，这对电极和沟道之间的横向电荷传输产生了不利的影响。我们的研究表明，在使用单层石墨烯电极的并五烯FET中获得的高场效应迁移率源于聚合物残基的外在效应以及高导电性、超薄的二维单层石墨烯电极的内在特性。
Organic electronic devices that use graphene electrodes have received considerable attention because graphene is regarded as an ideal candidate electrode material. Transfer and lithographic processes during fabrication of patterned graphene electrodes typically leave polymer residues on the graphene surfaces. However, the impact of these residues on the organic semiconductor growth mechanism on graphene surface has not been reported yet. Here, we demonstrate that polymer residues remaining on graphene surfaces induce a stand-up orientation of pentacene, thereby controlling pentacene growth such that the molecular assembly is optimal for charge transport. Thus, pentacene field-effect transistors (FETs) using source/drain monolayer graphene electrodes with polymer residues show a high field-effect mobility of 1.2 cm(2)/V s. In contrast, epitaxial growth of pentacene having molecular assembly of lying-down structure is facilitated by pi-pi interaction between pentacene and the clean graphene electrode without polymer residues, which adversely affects lateral charge transport at the interface between electrode and channel. Our studies provide that the obtained high field-effect mobility in pentacene FETs using monolayer graphene electrodes arises from the extrinsic effects of polymer residues as well as the intrinsic characteristics of the highly conductive, ultrathin two-dimensional monolayer graphene electrodes.