Irfan Ahmad, Chaudhry Aijaz Rasool, Muhammad Shabbir, Al-Sehemi Abdullah G
Department of Chemistry, Faculty of Science, King Khalid University, Abha 61413, P. O. Box 9004, Saudi Arabia; Research Center for Advanced Materials Science (RCAMS), King Khalid University, Abha 61413, P. O. Box 9004, Saudi Arabia.
Research Center for Advanced Materials Science (RCAMS), King Khalid University, Abha 61413, P. O. Box 9004, Saudi Arabia; Department of Physics, Faculty of Science, King Khalid University, Abha 61413, P. O. Box 9004, Saudi Arabia.
J Mol Graph Model. 2017 Aug;75:209-219. doi: 10.1016/j.jmgm.2017.05.017. Epub 2017 May 26.
Owing to their excellent electrochemical properties, graphenes found applications in several fields ranging from semiconductors, solar cells, field effect transistors, and nanoscale electronic devices as well as in nonlinear optical (NLO) applications. The structural features, electro-optical, charge transport and nonlinear optical properties of the boron-doped graphene (BG) compound 1 were studied using density functional theory methods The BG compound comprises a central electron deficient site of boron atoms, which can serve as electron acceptor while terminal alkoxy groups as donors leading to powerful donor-π-acceptor (D-π-A) configuration. The experimental crystal structure was successfully reproduced by optimized ground state geometry at PBE0/6-311G* level of theory for isolated molecule. The experimental lattice parameters, geometries, crystal presentation and alignment of molecules in the unit cells as well as their packing orientation of BG compound 1 was also efficiently reproduced by applying periodic boundary conditions (PBC) at PBE level. The comprehensive intramolecular charge transfer (CT) was realized from terminal rings of the HOMO to the electron deficient sites of boron atoms of the LUMO. The nature of BG compound 1 might be more towards hole transport even though its hole reorganization energy is twice than that of the electron one due to the significant higher hole transfer integral values. The superior hole transfer integrals and intrinsic mobility values of the BG compound 1 might lead remarkable hole transport contender as compared to many other organic materials. The narrow band gap, density of states profile, dielectric function, uniform conductivity functions and noteworthy electronic as well as CT properties revealed that the BG compound 1 might be proficient optoelectronic contestant having intermolecular CT as well as intramolecular CT with optimal stability. A comparison of static third-order polarizability <γ> of BG compound 1, as calculated in present investigation, was also performed with some standard NLO molecules as well as graphene nanoflakes. Moreover, longitudinal component γ of parent compound has been found 12 and 4 times larger than those of previously reported open-shell poly aromatic hydrocarbons (PAH). Interestingly, by increasing the donor ability, i.e., introduction of CHPhNH groups in place of OCH groups (BG compound 3) at terminal positions boosts the <γ> amplitude∼8 times than that of its parent BG compound 1.
由于其优异的电化学性能，石墨烯在多个领域得到了应用，包括半导体、太阳能电池、场效应晶体管、纳米级电子器件以及非线性光学（NLO）应用。使用密度泛函理论方法研究了硼掺杂石墨烯（BG）化合物1的结构特征、电光、电荷传输和非线性光学性质。BG化合物包含一个中心缺电子的硼原子位点，其可作为电子受体，而末端烷氧基作为供体，形成强大的供体-π-受体（D-π-A）构型。通过在PBE0/6-311G*理论水平上对孤立分子的基态几何结构进行优化，成功再现了实验晶体结构。通过在PBE水平上应用周期性边界条件（PBC），也有效地再现了BG化合物1的实验晶格参数、几何结构、晶体呈现以及分子在晶胞中的排列及其堆积取向。实现了从最高占据分子轨道（HOMO）的末端环到最低未占据分子轨道（LUMO）的硼原子缺电子位点的全面分子内电荷转移（CT）。尽管BG化合物1的空穴重组能是电子重组能的两倍，但由于空穴转移积分值显著更高，其性质可能更倾向于空穴传输。与许多其他有机材料相比，BG化合物1优异的空穴转移积分和本征迁移率值可能使其成为显著的空穴传输竞争者。窄带隙、态密度分布、介电函数、均匀电导率函数以及显著的电子和CT性质表明，BG化合物1可能是具有分子间CT以及分子内CT且具有最佳稳定性的高效光电器件竞争者。还将本研究中计算得到的BG化合物1的静态三阶极化率<γ>与一些标准NLO分子以及石墨烯纳米片进行了比较。此外，已发现母体化合物的纵向分量γ比先前报道的开壳多环芳烃（PAH）大12倍和4倍。有趣的是，通过提高供体能力，即在末端位置引入CHPhNH基团代替OCH基团（BG化合物3），<γ>幅度比其母体BG化合物1提高了约8倍。
