As nitrogen‐doped graphene has been widely applied in optoelectronic devices and catalytic reactions, in this work we have investigated where the nitrogen atoms tend to reside in the material and how they affect the electron density and spectroscopic properties from a theoretical point of view. DFT calculations on N‐doped hexagonal and rectangular graphene nanoflakes (GNFs) showed that nitrogen atoms locating on zigzag edges are obviously more stable than those on armchair edges or inside flakes, and interestingly, the N‐hydrogenated pyridine moiety could be preferable to pure pyridine moiety in large models. The UV–vis absorption spectra of these nitrogen‐doped GNFs display strong dependence on flake sizes, where the larger flakes have their major peaks in lower energy ranges. Moreover, the spectra exhibit different connections to various dopant types and positions: the graphitic‐type dopant species present large variety in absorption profiles, while the pyridinic‐type ones show extraordinary uniform stability and spectra independent of dopant positions/numbers and hence are hardly distinguishable from each other. © 2018 Wiley Periodicals, Inc.

中文翻译：

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氮掺杂石墨烯纳米薄片的理论研究：稳定性和光谱取决于掺杂剂类型和薄片尺寸

由于掺氮石墨烯已广泛应用于光电器件和催化反应，在这项工作中，我们从理论的角度研究了氮原子在材料中的位置以及它们如何影响电子密度和光谱特性。对 N 掺杂的六边形和矩形石墨烯纳米薄片 (GNF) 的 DFT 计算表明，位于锯齿形边缘的氮原子明显比扶手椅边缘或内部薄片上的氮原子更稳定，有趣的是，N-氢化吡啶部分可能优于纯吡啶大型模型中的部分。这些掺氮 GNF 的紫外-可见吸收光谱显示出对薄片尺寸的强烈依赖性，其中较大的薄片在较低的能量范围内具有主要峰。而且，光谱与各种掺杂剂类型和位置表现出不同的联系：石墨型掺杂剂种类在吸收分布方面表现出很大差异，而吡啶型掺杂剂则表现出非凡的均匀稳定性和光谱，与掺杂剂的位置/数量无关，因此几乎无法与每种掺杂剂区分开来其他。© 2018 Wiley Periodicals, Inc.