Runowski Marcin, Sobczak Szymon, Marciniak Jędrzej, Bukalska Ida, Lis Stefan, Katrusiak Andrzej
Adam Mickiewicz University, Faculty of Chemistry, Umultowska 89b, 61-614 Poznań, Poland.
Nanoscale. 2019 May 9;11(18):8718-8726. doi: 10.1039/c9nr02792k.
Gold nanorods (Au NRs), nanospheres and other nanoparticles display numerous superior physicochemical properties, such as resistance to oxidation and aggressive agents, strong enhancement of local electric field and a high absorption coefficient in the visible and near-infrared (NIR) range. The absorption peaks of surface plasmon resonance (SPR) in Au NRs are highly sensitive to their surrounding medium and to its refractive index (RI) changes. However, no applications of NRs for detecting phase transitions have been reported. Here, we show that Au NRs effectively detect phase transitions of compressed compounds, liquid and solid, by measuring their RI. Owing to the direct interaction of the NRs with their surrounding medium, its subtle RI changes can be observed by the use of high-pressure absorption vis-NIR spectroscopy. We have applied a Au NR-based sensor in a diamond anvil cell (DAC) for monitoring the phase transitions of compressed water, its freezing to ice VI and at the subsequent solid-solid phase transition to ice VII, and the monotonic compression and solid-solid phase transitions in urea and thiourea.
金纳米棒（Au NRs）、纳米球和其他纳米颗粒具有许多优异的物理化学性质，如抗氧化和抗侵蚀性、局部电场的强烈增强以及在可见光和近红外（NIR）范围内的高吸收系数。Au NRs中表面等离子体共振（SPR）的吸收峰对其周围介质及其折射率（RI）变化高度敏感。然而，尚未有关于NRs用于检测相变的应用报道。在此，我们表明Au NRs通过测量其RI有效地检测压缩化合物（液体和固体）的相变。由于NRs与其周围介质的直接相互作用，通过使用高压吸收可见近红外光谱可以观察到其细微的RI变化。我们已将基于Au NR的传感器应用于金刚石对顶砧（DAC）中，以监测压缩水的相变、其冻结成冰VI以及随后向冰VII的固-固相变，以及尿素和硫脲中的单调压缩和固-固相变。
