CHEN Xi , ZHANG Shengli

1 Department of Applied Physics, School of Physics and Optoelectronic Engineering, Xidian University, Xi’an 710071, P. R. China.

2 Department of Applied Physics, School of Science, Xi’An Jiaotong University, Xi’an 710049, P. R. China.

3 MOE Key Laboratory for Non-equilibrium Synthesis and Modulation of Condensed Matter, Xi’an Jiaotong University, Xi’an 710049, P. R. China.

Abstract: In recent years, the successful preparation of single-layer graphene, MoS2, and other two-dimensional materials has started a new era of two-dimensional materials. The potential applications of twodimensional materials in emerging electronics have drawn widespread attention. Two-dimensional carbon materials, with their unique properties, have become the research hotspot of condensed matter physics, nanoelectronics, and biological medicine. The remarkable success in preparing graphene provides additional possibilities for developing sensitive biodevices and medicine systems. However, graphene is gapless and thus is unsuitable for building nanoelectronic devices or biosensors due to the too low on/off current ratio. More than 20 years ago, graphyne and its family (viz. graphdiyne, graphyne-3, etc.), as hypothetical C allotropes, were theoretically predicted to be semiconductors with a layered structure. Recently, graphdiyne was successfully synthesized on the surface of copper via a cross-coupling reaction using hexaethynylbenzene. Graphdiyne, as a new two-dimensional carbon material with semiconductor properties and a unique porous structure, is more advantageous than graphene for nanoelectronic and biosensing applications. As the first discovered semiconducting two-dimensional carbon material, with independent intellectual property rights in China,graphdiyne has great research significance. Compared with graphene, graphdiyne has a unique structure with larger pores composed of high π-conjugated acetylenic bonds, which may facilitate strong adsorption to biomolecules. Therefore,further research is needed to reveal how the physical properties of graphdiyne can be modulated effectively to meet the requirements of practical applications. The interaction between biological molecules and materials is an important subject of research in condensed matter physics and materials science. Detailed understanding of the interactions between graphdiyne and small molecules may facilitate the development of advanced biological applications such as biosensors for the detection of biomolecules and living cells, drug delivery systems, and cell imaging technologies. In sensitive analysis,the ultimate goal is to achieve reliable detection of trace amounts of molecules. In this work, first-principles calculations were employed to investigate the electronic structure of graphdiyne nanoribbons and the adsorption of graphdiyne to small molecules. To improve the chemical response of graphdiyne to single molecules, we considered modifying graphdiyne by doping 3d transition metal atoms. We chose Sc and Ti, which have the largest adsorption energies on graphdiyne, and studied the room-temperature stabilities of Sc- and Ti-doped graphdiyne and the possibility of using Sc- and Ti-doped graphdiyne as materials for molecular sensing. Finally, we investigated the interaction between graphdiyne and amino acid molecules and discovered that the dispersion force plays a large role in the interaction. The influence of amino acids on the electronic transport properties of graphdiyne was also studied, and the potential applications of graphdiyne to biosensors were investigated.

Key Words: Graphdiyne; Two-dimensional material; Electronic transport; Nanodevice

1 引言

碳元素是人类最早认识的元素之一，也是自然界成键结构最丰富的元素1。碳元素可构成许多具有特殊性质的材料2–6。在古代人们便发现了碳的同素异形体，如石墨和金刚石。随着近二十年来实验技术的发展，人们成功制备了许多不同结构的碳纳米结构，对材料技术的进步具有里程碑意义。含碳材料由于其具有的独特电子特性，在某些方面有许多先进应用，如太阳能电池，有机发光二极管，场效应管，化学传感器等。

2004年，Geim等人以单晶石墨为原料，得到了单原子层的石墨烯7,8。此后，人们发现了越来越多的二维材料。二维材料电子特性的潜在应用引起了广泛的关注。由于二维单原子层具有特殊的结构和独特的物理性质8–11，因此一直是众多领域中科学工作者研究的热点。然而，零带隙的石墨烯不适用于制备晶体管等电子器件。早在数十年前，就有人从理论上预测出一类由sp和sp2杂化的碳原子构成碳的同素异形体—石墨炔12,13。石墨炔具有平面层状结构，是由碳六元环和炔键构成的半导体。近年来，中国科学院化学研究所的李玉良院士课题组在实验上首次在铜表面成功制备出γ-石墨二炔(属于石墨炔中的一种，以下简称石墨二炔)14,15。石墨二炔是第一种具有半导体性质的碳的同素异形体，带隙与硅接近，比石墨烯更适用于制备纳米电子器件15–17，是新一代场效应管材料的候选者。

石墨二炔是我国独立研发并具有自主知识产权的新型二维碳材料。……