Geballe Laboratory for Advanced Materials , Stanford University , Stanford , California 94305 , United States.
Exponent Inc., Menlo Park , California 94025 , United States.
Nano Lett. 2018 Mar 14;18(3):1699-1706. doi: 10.1021/acs.nanolett.7b04739. Epub 2018 Feb 9.
Explosives, propellants, and pyrotechnics are energetic materials that can store and quickly release tremendous amounts of chemical energy. Aluminum (Al) is a particularly important fuel in many applications because of its high energy density, which can be released in a highly exothermic oxidation process. The diffusive oxidation mechanism (DOM) and melt-dispersion mechanism (MDM) explain the ways powders of Al nanoparticles (NPs) can burn, but little is known about the possible use of plasmonic resonances in NPs to manipulate photoignition. This is complicated by the inhomogeneous nature of powders and very fast heating and burning rates. Here, we generate Al NPs with well-defined sizes, shapes, and spacings by electron beam lithography and demonstrate that their plasmonic resonances can be exploited to heat and ignite them with a laser. By combining simulations with thermal-emission, electron-, and optical-microscopy studies, we reveal how an improved control over NP ignition can be attained.
爆炸物、推进剂和烟火剂是能够储存并迅速释放大量化学能的能量材料。由于其高能量密度，铝 (Al) 在许多应用中是一种特别重要的燃料，其能量可以在高度放热的氧化过程中释放出来。扩散氧化机制 (DOM) 和熔融分散机制 (MDM) 解释了纳米 Al 颗粒 (NPs) 粉末燃烧的方式，但对于等离子体共振在 NPs 中可能用于控制光引发的应用知之甚少。这一点很复杂，因为粉末的不均匀性以及非常快的加热和燃烧速率。在这里，我们通过电子束光刻生成具有明确定义的尺寸、形状和间距的 Al NPs，并证明可以利用它们的等离子体共振用激光加热和点燃它们。通过将模拟与热发射、电子和光学显微镜研究相结合，我们揭示了如何更好地控制 NP 点火。
