Ishisone Kana, Ori Guido, Boero Mauro
University of Strasbourg, Institut de Physique et Chimie des Matériaux de Strasbourg, CNRS, UMR 7504, 23 rue du Loess, F-67034, France.
Phys Chem Chem Phys. 2022 Apr 20;24(16):9597-9607. doi: 10.1039/d2cp00741j.
We provide a microscopic insight, both structural and electronic, into the multifold interactions occurring in the ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide [EMIM][TFSI] currently targeted for applications in next-generation low-power electronics and optoelectronic devices. To date, practical applications have remained hampered by the lack of fundamental understanding of the interactions occurring both inside the IL and at the interface with the substrate. Our first principles dynamical simulations provide accurate insights into the nature of bonding and non-bonding interactions, dynamical conformational changes and induced dipole moments, along with their statistical distributions, of this ionic liquid, that have so far not been completely unraveled. The mobilities of the two ionic species are obtained by long-lasting dynamical simulations at finite temperature, allowing simultaneous monitoring and quantification of the isomerization occurring in the IL. Moreover, a thorough analysis of the electronic structure and partial charge distributions characterizing the two components, the cation and anion, allow rationalization of the nature of the electrostatic interactions, hydrogen bonding properties of the two ionic counterparts, and the infra-red and dielectric response of the system, especially in the low frequency range, for the full characterization of the IL.
我们从微观角度，包括结构和电子方面，深入研究了离子液体1-乙基-3-甲基咪唑双（三氟甲基磺酰）亚胺（[EMIM][TFSI]）中发生的多种相互作用，该离子液体目前被用于下一代低功耗电子和光电器件。迄今为止，由于对离子液体内部以及与基底界面处发生的相互作用缺乏基本认识，实际应用一直受到阻碍。我们的第一性原理动力学模拟为这种离子液体的键合和非键合相互作用的本质、动态构象变化和诱导偶极矩及其统计分布提供了准确的见解，而这些到目前为止尚未完全阐明。通过在有限温度下进行长时间的动力学模拟，获得了两种离子物种的迁移率，从而能够同时监测和量化离子液体中发生的异构化。此外，对表征阳离子和阴离子这两个组分的电子结构和部分电荷分布进行全面分析，有助于阐明静电相互作用的本质、两种离子对应物的氢键性质以及系统的红外和介电响应，特别是在低频范围内，从而对离子液体进行全面表征。
