Limits of Pseudoelasticity in Gold Nanocrystals
Limits of Pseudoelasticity in Gold Nanocrystals
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DOI：
10.1021/acs.jpcc.1c07723
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发表时间：
2021-12-13
影响因子：
3.7
通讯作者：
Hanson, Lindsey A.
中科院分区：
文献类型：
--
作者：
Harkins, K. Anika;Boettner, Jonas;Hanson, Lindsey A.
金属纳米晶体中的伪弹性允许从比其块状对应物大得多的应变中恢复形状。这种迷人的特性可用于设计自我修复或可重构材料，但为了充分利用其可能性，需要更深入地了解其机制和局限性。例如，在没有引入塑性损伤的情况下，室温赝弹性是否会发生在所有金属纳米晶体中，目前尚不清楚。在这里，我们报告了在金刚石砧细胞中使用非流体静力压缩金纳米晶体的最大压力范围，最高可达11.4 GPa。局部表面等离子体共振的光学吸收光谱用于无创监测粒子形状和结晶度的变化，分别由等离子体共振峰的位置和强度表示。我们发现，虽然压缩到所有测试的压力后都可以完全恢复形状，但不可逆的晶体缺陷仅在类似于2.5 GPa的阈值以上才会引入。通过这种方式，我们建立了金纳米晶体在中等载荷下压缩后完全恢复假弹性形状的能力，以及在高载荷下开始有限的假弹性行为的能力。这项工作为未来研究各种金属纳米晶体的伪弹性变形极限奠定了基础。
Pseudoelasticity in metal nanocrystals allows for shape recovery from strains much larger than their bulk counterparts. This fascinating property could be used to engineer self-healing or reconfigurable materials, but to take full advantage of its possibilities, a deeper understanding of its mechanism and limitations is needed. For instance, it is unknown whether room-temperature pseudoelasticity can occur in all metal nanocrystals without the introduction of plastic damage. Here we report the use of nonhydrostatic compression of gold nanocrystals in a diamond anvil cell to a range of maximum pressures, up to 11.4 GPa. Optical absorbance spectroscopy of the localized surface plasmon resonance is used to noninvasively monitor changes in particle shape and crystallinity, as indicated by the plasmon resonance peak position and intensity, respectively. We find that while complete shape recovery occurs following compression to all pressures tested, irreversible crystalline defects are only introduced above a threshold of similar to 2.5 GPa. In this way, we establish the capacity of gold nanocrystals to undergo complete pseudoelastic shape recovery following compression under moderate loads as well as the onset of limited pseudoelastic behavior at higher loads. This work lays a foundation for future investigations of the limits of pseudoelastic deformation in a wide variety of metal nanocrystals.