Quantum dots (QDs) are semiconductor nanocrystals extensively applied as optoelectronic devices, sensors and fluorescent probes for (bio)molecular species. Silver chalcogenides (i.e., sulfide, selenide and telluride) are examples of I–VI-based QDs, which have low toxicity and excellent colloidal stability and hold great promise for applications including photovoltaics, lighting and displays as well as biomedical imaging. In this study, we investigated the potential SEIRA effect of silver selenide QDs stabilized via mercaptosuccinic acid (Ag₂Se–MSA QDs) in aqueous suspension for amplifying the IR signature of a variety of dye molecules. For this purpose, time-resolved attenuated total reflection (ATR) spectra were recorded after the deposition of aqueous dye vs. dye/QD solutions until total evaporation of the liquid at an Si ATR waveguide surface. As main results, experimental enhancement factors (EF) of up to 10.9 were obtained, which indicates that Ag₂Se–MSA QDs are able to enhance IR signatures effectively. In addition, an approach based on principal component analysis (PCA) and Euclidian distances was introduced to determine a novel parameter termed the ‘multivariate enhancement factor’ (MEF), which may be more suitable for multivariate studies performed using design of experiments (DoE) to optimize the experimental conditions for SEIRA studies. These PCA studies also evidenced how the enhancement effect by Ag₂Se–MSA QDs may indeed occur, and corroborate that chemometrics tools not only aid in data analysis, but may also improve the understanding and knowledge on SEIRA systems.

中文翻译：

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使用硒化银量子点的表面增强红外吸收光谱

量子点（QD）是半导体纳米晶体，广泛用作（生物）分子物种的光电器件，传感器和荧光探针。硫属硫化物（即硫化物，硒化物和碲化物）是基于I–VI的量子点的实例，它们毒性低，胶体稳定性好，在光伏，照明和显示器以及生物医学成像等应用中具有广阔的前景。在这项研究中，我们研究了通过巯基琥珀酸（Ag ₂ Se–MSA QDs）稳定的硒化银量子点在水悬浮液中的SEIRA潜在效应，以放大各种染料分子的红外特征。为此，在沉积水性染料后记录时间分辨的衰减全反射（ATR）光谱与染料/ QD溶液相比，直到Si ATR波导表面上的液体完全蒸发。作为主要结果，获得了高达10.9的实验增强因子（EF），这表明Ag ₂ Se–MSA QD能够有效增强IR特征。此外，还引入了一种基于主成分分析（PCA）和欧几里得距离的方法来确定一个称为“多变量增强因子”（MEF）的新参数，该参数可能更适合使用实验设计（DoE）进行的多变量研究优化SEIRA研究的实验条件。这些PCA研究还证明了Ag ₂的增强作用Se-MSA QD确实可能发生，并证实化学计量学工具不仅有助于数据分析，而且还可以增进对SEIRA系统的理解和知识。