Molecular Alignment and Electronic Structure of N,N′-Dibutyl-3,4,9,10-perylene-tetracarboxylic-diimide Molecules on MoS2 Surfaces

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• 作者：ArramelXinmao Yin ; Qixing Wang ; Yu J. Zheng ; Zhibo Song ; Mohammad H. bin Hassan ; Dianyu Qi ; Jishan Wu ; Andrivo Rusydi ; Andrew T. S. Wee
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2017
• 出版时间：February 15, 2017
• 年：2017
• 卷：9
• 期：6
• 页码：5566-5573
• 全文大小：502K
• ISSN：1944-8252

文摘

The molecular orientation of organic semiconductors on a solid surface could be an indispensable factor to determine the electrical performance of organic-based devices. Despite its fundamental prominence, a clear description of the emergent two-dimensional layered material–organic interface is not fully understood yet. In this study, we reveal the molecular alignment and electronic structure of thermally deposited N,N′-dibutyl-3,4,9,10-perylene-dicarboximide (PTCDI-C4) molecules on natural molybdenum disulfide (MoS₂) using near-edge X-ray absorption fine structure spectroscopy (NEXAFS). The average tilt angle determination reveals that the anisotropy in the π* symmetry transition of the carbon K-edge (284–288 eV range) is present at the sub-monolayer regime. Supported by ultraviolet photoelectron spectroscopy (UPS), X-ray photoelectron spectroscopy (XPS), and resonant photoemission spectroscopy (RPES) measurements, we find that our spectroscopic measurements indicate a weak charge transfer established at the PTCDI-C4/MoS₂ interface. Sterical hindrance due to the C4 alkyl chain caused tilting of the molecular plane at the initial thin film deposition. Our result shows a tunable interfacial alignment of organic molecules on transition metal dichalcogenide surfaces effectively enhancing the electronic properties of hybrid organic–inorganic heterostructure devices.