Lee Kee Eun, Hesketh Amelia V, Kelly Timothy L
Department of Chemistry, University of Saskatchewan, 110 Science Place, Saskatoon, SK S7N 5C9, Canada.
Phys Chem Chem Phys. 2014 Jun 28;16(24):12407-14. doi: 10.1039/c4cp00954a.
Anisotropic metal nanoparticles have found use in a variety of plasmonic applications because of the large near-field enhancements associated with them; however, the very features that give rise to these enhancements (e.g., sharply curved edges and tips) often have high surface energies and are easily degraded. This paper describes the stability and degradation mechanisms of triangular silver, gold-coated silver, and gold nanoprisms upon exposure to a wide variety of adverse conditions, including halide ions, thiols, amines and elevated temperatures. The silver nanoprisms were immediately and irreversibly degraded under all of the conditions studied. In contrast, the core-shell Ag@Au nanoprisms were less susceptible to etching by chlorides and bromides, but were rapidly degraded by iodides, amines and thiols by a different degradation pathway. Only the pure gold nanoprisms were stable to all of the conditions tested. These results have important implications for the suitability of triangular nanoprisms in many applications; this is particularly true in biological or environmental fields, where the nanoparticles would inevitably be exposed to a wide variety of chemical stimuli.
各向异性金属纳米粒子因其具有与它们相关的大的近场增强效应而在各种等离子体应用中得到了应用；然而，产生这些增强效应的特征（例如，急剧弯曲的边缘和尖端）往往具有高表面能且容易降解。本文描述了三角形银、金包覆银和金纳米棱柱在暴露于各种不利条件（包括卤离子、硫醇、胺和高温）下的稳定性和降解机制。在所研究的所有条件下，银纳米棱柱立即且不可逆地降解。相比之下，核壳Ag@Au纳米棱柱对氯化物和溴化物的蚀刻不太敏感，但通过不同的降解途径被碘化物、胺和硫醇迅速降解。只有纯金纳米棱柱对所有测试条件都稳定。这些结果对于三角形纳米棱柱在许多应用中的适用性具有重要意义；在生物或环境领域尤其如此，在这些领域中纳米粒子不可避免地会暴露于各种化学刺激下。
