Sharma Anamika, Ramanaiah Dantham Venkata
Department of Physics, Indian Institute of Technology Patna, Bihar 801103, India.
Department of Physics, Indian Institute of Technology Patna, Bihar 801103, India.
Spectrochim Acta A Mol Biomol Spectrosc. 2024 Sep 5;317:124431. doi: 10.1016/j.saa.2024.124431. Epub 2024 May 9.
Herein, we report the Raman spectroscopy of crystal violet (CV) and IR-780 Iodide molecules dispersed on the monolayer graphene film (MGF). In the CV-MGF system, the enhancement in the Raman scattering of CV molecules is observed irrespective of the location probed during the spectral measurements. This enhancement is due to the charge transfer from the MGF to CV molecules. However, in the case of the IR-780 Iodide - MGF system, the enhancement of Raman scattering of dye molecules or MGF is observed strongly depending upon the probed location. These observations indicate that the charge transfer is irreversible and reversible in the CV-MGF and IR-780 Iodide-MGF systems, respectively. Importantly, for the first time, this experimental study revealed that enhancing the Raman scattering of MGF is possible through the "chemical mechanism" with suitable dye molecules apart from the "electromagnetic mechanism" with plasmonic hot spots of the metal nanoparticles and photonic nanojets of single dielectric microparticles.
在此，我们报道了分散在单层石墨烯薄膜（MGF）上的结晶紫（CV）和IR-780碘化物分子的拉曼光谱。在CV-MGF系统中，无论在光谱测量期间探测的位置如何，都观察到CV分子的拉曼散射增强。这种增强是由于电荷从MGF转移到CV分子。然而，在IR-780碘化物-MGF系统的情况下，根据探测位置的不同，强烈观察到染料分子或MGF的拉曼散射增强。这些观察结果表明，电荷转移在CV-MGF和IR-780碘化物-MGF系统中分别是不可逆和可逆的。重要的是，首次通过该实验研究揭示，除了利用金属纳米颗粒的等离子体热点和单个介电微粒的光子纳米射流的“电磁机制”外，还可以通过与合适的染料分子的“化学机制”来增强MGF的拉曼散射。
