Pszona Maria, Gawinkowski Sylwester, Jäger Regina, Kamińska Izabela, Waluk Jacek
Institute of Physical Chemistry, Polish Academy of Sciences, 01-224 Warsaw, Kasprzaka 44/52, Poland.
Institute of Physical and Theoretical Chemistry and LISA, University of Tübingen, Auf der Morgenstelle 18, D-72076 Tübingen, Germany.
J Chem Phys. 2022 Jan 7;156(1):014201. doi: 10.1063/5.0074840.
The surface-enhanced Raman spectroscopy (SERS) detection limit strongly depends on the molecular structure, which we demonstrate for a family of tert-butyl-substituted porphycenes. Even though the investigated species present very similar photophysical properties, the ratio between the SERS signal and fluorescence background depends on the number of bulky tert-butyl groups. Moreover, the probability of single molecule detection systematically drops with the number of the moieties attached to the pyrrole ring. As steric hindrance is the only significantly changing feature among the studied chromophores, we attribute the observed phenomena to the spatial structure. We also show that the sensitivity of the SERS technique can be improved by lowering the temperature. We managed to observe single-molecule spectra for derivatives for which this was unattainable at room temperature.
表面增强拉曼光谱（SERS）的检测限很大程度上取决于分子结构，我们通过一族叔丁基取代的卟吩对此进行了论证。尽管所研究的物种呈现出非常相似的光物理性质，但SERS信号与荧光背景之间的比率取决于庞大叔丁基的数量。此外，单分子检测的概率会随着连接到吡咯环上的基团数量而系统性地下降。由于空间位阻是所研究发色团中唯一显著变化的特征，我们将观察到的现象归因于空间结构。我们还表明，通过降低温度可以提高SERS技术的灵敏度。我们成功观测到了在室温下无法实现的衍生物的单分子光谱。
