Production and investigation of sensor devices based on plasmonic noble metal (Au, Ag) nanoparticles

Plasmonic nanoparticles have been studied extensively by scientists in the last two decades. When noble metal nanoparticles interact with light, free electrons on the metal surface are forced to oscillate and surface plasmon resonance (SPR) occurs at a certain wavelength. This enormous optical phenomenon is a very delicate process and depends on the nanoparticle's size, shape and surrounding environment. The reason for using plasmonic nanoparticles as sensors; their ability to amplify signals very well. The Localized Surface Plasmon Resonance (LSPR) property of metallic nanoparticles is widely used for chemical and biological sensing. Selective sensor property of molecules using functionalized nanoparticles; It has become an important interdisciplinary research topic in the fields of chemistry, biology and materials science. Noble metals, especially gold (Au) and silver (Ag) nanoparticles, show unique and tunable plasmonic properties. The size, shape and response of these metal nanostructures to the local environment can be controlled, and changes in wavelength can be measured by shifts in the LSPR peaks. In this study, 20-100 nm Au and Ag noble metal nanoparticles (NP) were produced using Pulse Laser Deposition (PLD) technique and very sensitive optical properties of NPs were investigated using LSPR technique. The morphology of the produced nanoparticles was determined and characterized using scanning electron microscopy (SEM). In addition, UV-Vis-NIR spectroscopy technique was used to determine the LSPR absorption peaks of NPs. Au and Ag NPs were deposited on the glass substrate depending on the laser deposition times. As the laser deposition time of the produced NPs increased, both the size of the formed NPs and the number of nanoparticles per unit surface increased. It was observed that the shape of Au and Ag NPs produced based on SEM images was spherical. When the UV-Vis-NIR spectra of Au and Ag NPs were examined, it was observed that the LSPR peaks shifted to longer wavelengths (redshift) as the laser deposition times increased. After the LSPR peaks of the plasmonic nanoparticles were characterized, Protein A and Biotin molecules were attached to the Silver and Gold NPs to detect the sensor properties. LSPR peak shifts of bound NPs could be determined. Keywords: Ag, Au, LSPR, Plasmonic nanoparticles (NP), sensor, PLD