Fiber optic raman spectrometer with in situ probing capabilities for characterization of metal nanoparticles and metallodielectric composite materials

点击翻译按钮获取中文摘要

Nanoscience and nanotechnology play an increasingly important role in our life.  Metal nanoparticles and nanocomposites have been known to mankind for centuries as a ruby gold glass. Nowadays, extensive studies of the prominent optical properties of metal nanoparticles responsible for glass colouration are driven by technological applications of plasmonics and photonics and became one of the major subjects of nanoscience. Raman spectroscopy, being more discriminatory compared to commonly used IR spectroscopy, offers great advantages in characterization of organic molecules. However, Raman scattering typically has very weak signal intensity, which prevented its wide-spread application even with the advent of powerful lasers. That is where gold and especially silver nanoparticles offer tremendous benefits of boosting a weak Raman signal in the vicinity of the metal surface up to ten orders of magnitude.  The Raman spectroscopy will be applied in our research in two major directions. First is optimization of the nanoparticle synthesis and understanding synthetic mechanisms. For the most part, mechanism elucidation has been hampered by considerable complexity of in-situ monitoring on a nanoscale. However, recent advances in fiber optic Raman instrumentation brought powerful research tools that can be readily used for in situ monitoring. In situ monitoring will allow us to gain better understanding of the nanoparticle formation and will be highly advantageous for our research in chiral nano-building blocks. Second direction will be design of silver nanoparticles and nanocomposites with optimized enhancement of the Raman signal that has been shown to have an ultimate capability of single-molecule detection. Ability to prepare such composite materials with highly-reproducible properties will be of tremendous value for analytical detection, e.g. biodiagnostics.   In summary, recent technological developments brought very affordable instruments without compromising quality and capabilities that makes the proposed Raman setup a very cost-effective, efficient and indispensable characterization tool for our ongoing research in metal nanoparticles and nanocomposites.