In the present study, we investigate the adsorption characteristics of six different ionic liquids (ILs) on a fully-fluorinated graphene (fluorographene, FG) surface using electronic structure studies and associated analysis methods. A systematic comparison of differences in IL binding energies (ΔE_b) with fluorographene, graphene and hexagonal boron nitride surfaces indicates that fluorination strongly decreases the binding energy compared to the other two surfaces, hence resulting in the binding energetics: ΔE_{b (Graphene…IL)} > ΔE_{b (Hexagonal boron-nitride…IL)} > ΔE_{b (Fluorographene…IL)}. To probe the reasons for this difference, quantum theory of atoms in molecules (QTAIM) analysis and non-covalent interactions (NCI) analyses were carried out. Results indicate that the stability of complexes of FG surface with ILs (FG…IL) arises only due to the presence of the expected weak non-covalent intermolecular interactions. The calculation of charge transfers by employing the ChelpG method shows that the interaction of ILs with FG surface generally induces a negative charge on the FG surface. Furthermore, these interactions lead to a decrease of the HOMO-LUMO energy gap (E_g) of the FG surface, enhancing its electrical conductivity. In addition, a detailed analysis of the global molecular descriptors including the Fermi energy level (E_FL), work function (WF), electronic chemical potential (μ), chemical hardness (η), global softness (S) and electrophilicity index (ω) was carried out for both the FG surface alone and the adsorbed complexes showing that there are small, but meaningful, differences in the reactivity of the surface depending on the nature of the IL. Finally, time-dependent DFT (TD-DFT) calculations of the optical properties of FG surface and FG…IL complexes reveal that the absorption spectrum of the FG surface undergoes a red shift following IL adsorption. This study demonstrates that FG provides a useful complementary tool to graphene and boron nitride materials, allowing for the fine-tuning of the optoelectronic properties of these monolayer materials. These results will assist in the development of these types of ILs for applications in optoelectronics.

在本研究中，我们使用电子结构研究和相关分析方法研究了六种不同离子液体（ILs）在全氟化石墨烯（氟代石墨烯，FG）表面上的吸附特性。在IL结合能差（ΔE进行系统比较_b与fluorographene，石墨烯和六方氮化硼表面）表示的氟化强烈降低的结合能比其他两个表面，因此导致在所述结合能量学：ΔE _{B（石墨... IL ）}  > _{ΔEb （六方氮化硼…IL）}  > _{ΔEb（氟化石墨烯…IL）}。为了探究产生这种差异的原因，进行了分子中原子的量子理论（QTAIM）分析和非共价相互作用（NCI）分析。结果表明，FG表面与ILs的复合物（FG…IL）的稳定性仅是由于预期的弱非共价分子间相互作用的存在而产生的。通过使用ChelpG方法进行的电荷转移计算表明，IL与FG表面的相互作用通常会在FG表面感应负电荷。此外，这些相互作用导致FG表面的HOMO-LUMO能隙（E _g）减小，从而增强了其电导率。此外，对包括费米能级（E _FL），仅对FG表面和吸附的复合物进行了功函数（WF），电子化学势（μ），化学硬度（η），整体柔软度（S）和亲电指数（ω） ，但有意义的是，表面活性的差异取决于IL的性质。最后，对FG表面和FG…IL配合物的光学性质进行时变DFT（TD-DFT）计算后发现，IL吸附后，FG表面的吸收光谱发生红移。这项研究表明，FG为石墨烯和氮化硼材料提供了有用的补充工具，可以对这些单层材料的光电特性进行微调。这些结果将有助于开发这些类型的IL，以用于光电子学。