Shashikala H B Mihiri, Nicolas Chantel I, Wang Xiao-Qian
Department of Physics, Clark Atlanta University, Atlanta, Georgia 30314, United States.
J Phys Chem C Nanomater Interfaces. 2012 Dec 13;116(49):26102-26105. doi: 10.1021/jp311269c. Epub 2012 Nov 22.
Noncovalent functionalization provides an effective way to modulate the electronic properties of graphene. Recent experimental work has demonstrated that hybrids of dipolar phototransductive molecules tethered to graphene are reversibly tunable in doping. We have studied the electronic structure characteristics of chromophore/graphene hybrids using dispersion-corrected density functional theory. The Dirac point of noncovalently functionalized graphene shifts upward via cis-trans isomerism, which is attributed to a change in the chromophore's dipole moment. Our calculation results reveal that the experimentally observed reversible doping of graphene is attributed to the change in charge transfer between the light-switchable chromophore and graphene via isomerization. Furthermore, we show that by varying the electric field perpendicular to the supramolecular functionalized graphene, additional tailoring of graphene doping can be accomplished.
非共价功能化提供了一种调节石墨烯电子性质的有效方法。最近的实验工作表明，与石墨烯相连的偶极光导分子的杂化物在掺杂方面是可逆可调的。我们使用色散校正密度泛函理论研究了发色团/石墨烯杂化物的电子结构特征。非共价功能化石墨烯的狄拉克点通过顺反异构向上移动，这归因于发色团偶极矩的变化。我们的计算结果表明，实验观察到的石墨烯可逆掺杂归因于光开关发色团与石墨烯之间通过异构化引起的电荷转移变化。此外，我们表明，通过改变垂直于超分子功能化石墨烯的电场，可以实现对石墨烯掺杂的进一步调控。
