Abstract The flexoelectric and electronic properties of zig-zag graphene nanoribbons are explored under mechanical bending using state of the art first principles calculations. A linear dependence of the bending induced out of plane polarization on the applied strain gradient is found. The inferior flexoelectric properties of graphene nanoribbons can be improved by more than two orders of magnitude by hydrogen and fluorine functionalization (CH and CF nanoribbons). A large out of plane flexoelectric effect is predicted for CF nanoribbons. The origin of this enhancement lies in the electro-negativity difference between carbon and fluorine atoms, which breaks the out of plane charge symmetry even for a small strain gradient. The flexoelectric effect can be further improved by co-functionalization with hydrogen and fluorine (CHF Janus-type nanoribbon), where a spontaneous out of plane dipole moment is formed even for flat nanoribbons. We also find that bending can control the charge localization of valence band maxima and therefore enables the tuning of the hole effective masses and band gaps. These results present an important advance towards the understanding of flexoelectric and electronic properties of hydrogen and fluorine functionalized graphene nanoribbons, which can have important implications for flexible electronic applications.

中文翻译：

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通过功能化调节锯齿形石墨烯纳米带的挠曲电性和电子特性

摘要 使用最先进的第一性原理计算，在机械弯曲下探索了锯齿形石墨烯纳米带的挠曲电和电子特性。发现了平面极化引起的弯曲对施加的应变梯度的线性相关性。石墨烯纳米带较差的挠曲电性能可以通过氢和氟官能化（CH 和 CF 纳米带）提高两个数量级以上。CF 纳米带预计会出现大的平面外挠电效应。这种增强的起源在于碳原子和氟原子之间的电负性差异，即使对于小应变梯度，这也打破了面外电荷对称性。通过与氢和氟（CHF Janus 型纳米带）的共官能化，可以进一步改善挠曲电效应，即使对于扁平纳米带，也会形成自发的平面外偶极矩。我们还发现弯曲可以控制价带最大值的电荷局部化，因此可以调整空穴有效质量和带隙。这些结果为理解氢和氟功能化石墨烯纳米带的柔性电和电子特性取得了重要进展，这对柔性电子应用具有重要意义。我们还发现弯曲可以控制价带最大值的电荷局部化，因此可以调整空穴有效质量和带隙。这些结果为理解氢和氟功能化石墨烯纳米带的柔性电和电子特性取得了重要进展，这对柔性电子应用具有重要意义。我们还发现弯曲可以控制价带最大值的电荷局部化，因此可以调整空穴有效质量和带隙。这些结果为理解氢和氟功能化石墨烯纳米带的柔性电和电子特性取得了重要进展，这对柔性电子应用具有重要意义。