Department of Materials Science and Engineering, University of Maryland, College Park, MD 20742, USA.
Molecules. 2023 Jan 18;28(3):953. doi: 10.3390/molecules28030953.
Interfaces formed by high energy density materials and metal oxides present intriguing new opportunities for a large set of novel applications that depend on the control of the energy release and initiation of explosive chemical reactions. We studied the role of structural defects at a MgO surface in the modification of electronic and optical properties of the energetic material TNT (2-methyl-1,3,5-trinitrobenzene, also known as trinitrotoluene, CHNO) deposited at the surface. Using density functional theory (DFT)-based solid-state periodic calculations with hybrid density functionals, we show how the control of chemical explosive reactions can be achieved by tuning the electronic structure of energetic compound at an interface with oxides. The presence of defects at the oxide surface, such as steps, kinks, corners, and oxygen vacancies, significantly affects interfacial properties and modifies electronic spectra and charge transfer dynamics between the oxide surface and adsorbed energetic material. As a result, the electronic and optical properties of trinitrotoluene, mixed with an inorganic material (thus forming a composite), can be manipulated with high precision by interactions between TNT and the inorganic material at composite interfaces, namely, by charge transfer and band alignment. Also, the electron charge transfer between TNT and MgO surface reduces the decomposition barriers of the energetic material. In particular, it is shown that surface structural defects are critically important in the photodecomposition processes. These results open new possibilities for the rather precise control over the decomposition initiation mechanisms in energetic materials by optical excitations.
高能密度材料与金属氧化物形成的界面为一系列新型应用提供了有趣的新机会，这些应用依赖于控制能量释放和引发爆炸化学反应。我们研究了 MgO 表面结构缺陷在控制含能材料 TNT（2-甲基-1,3,5-三硝基苯，也称为三硝基甲苯，CHNO）沉积表面电子和光学性质方面的作用。我们使用基于密度泛函理论（DFT）的固态周期性计算与混合密度泛函，展示了如何通过调整界面上含能化合物的电子结构来控制化学爆炸反应。氧化物表面缺陷的存在，如台阶、扭结、拐角和氧空位，显著影响界面性质，并改变氧化物表面和吸附含能材料之间的电子光谱和电荷转移动力学。结果表明，通过 TNT 与复合材料界面处无机材料之间的相互作用（即通过电荷转移和能带排列），可以高精度地操纵与无机材料混合的三硝基甲苯（从而形成复合材料）的电子和光学性质。此外，TNT 和 MgO 表面之间的电子电荷转移降低了含能材料的分解势垒。特别是，研究表明表面结构缺陷在光降解过程中至关重要。这些结果为通过光学激发对含能材料的分解引发机制进行相当精确的控制开辟了新的可能性。
