Artyukhov Vasilii I, Gupta Sunny, Kutana Alex, Yakobson Boris I
Department of Materials Science and NanoEngineering, and §Department of Chemistry, Rice University, Houston 77005 Texas, United States.
Quantlab Financial, Houston, Texas 77046, United States.
Nano Lett. 2020 May 13;20(5):3240-3246. doi: 10.1021/acs.nanolett.9b05345. Epub 2020 Apr 29.
The effect of flexoelectric voltage on the electronic and optical properties of single- and double-wall carbon nanotubes is evaluated by the first-principles calculations. The voltage between the inner channel of curved carbon nanostructures and their surroundings scales linearly with nanotube wall curvature and can be boosted/reversed by appropriate outer wall functionalization. We predict and verify computationally that in double-wall nanotubes, flexoelectricity causes a straddling to staggered band gap transition. Accurate band structure calculations taking into account quasiparticle corrections and excitonic effects lead to an estimated critical diameter of ∼24 Å for this transition. Double-wall nanotubes above this diameter have staggered band alignment and could be potentially used for charge separation in photovoltaic devices.
通过第一性原理计算评估了挠曲电电压对单壁和双壁碳纳米管电子和光学性质的影响。弯曲碳纳米结构内通道与其周围环境之间的电压与纳米管壁曲率呈线性关系，并且可以通过适当的外壁功能化来增强/反转。我们通过计算预测并验证，在双壁纳米管中，挠曲电会导致从跨带隙到交错带隙的转变。考虑到准粒子修正和激子效应的精确能带结构计算得出，这一转变的临界直径估计约为24 Å。直径大于此值的双壁纳米管具有交错的能带排列，可潜在地用于光伏器件中的电荷分离。
