Plasmonic Properties of Halloysite Nanotubes with Immobilized Silver Nanoparticles for Applications in Surface‐Enhanced Raman Scattering

Abstract

Halloysite nanotubes (HNTs) with surface-immobilized silver (Ag) nanoparticles (NPs) are explored as nano-templates for the surface-enhanced Raman scattering (SERS). The structure and plasmonic properties of HNTs/ Ag nanocomposite during storage in water are checked by means of the transmission electron microscopy and optical absorption spectroscopy, respectively. A remarkable SERS response is observed for and the SERS activity of HNTs/Ag stored in water for 1 week decreases by several times. The observed SERS-activity is explained by desired morphology of Ag NP distribution on the surface of HNTs, which is modified during storage in aqueous medium. The revealed SERS activity of HNTs/Ag nanocomposites seems to be promising for their application in biosensorics.

Halloysite Nanotubes with Immobilized Plasmonic Nanoparticles for Biophotonic Applications

“…For example, a prodigiosin-HNT-based nanoformulation (p-HNTs) and its effects on the viability of malignant and non-malignant cells have been demonstrated [10]. NPs of plasmonic metals attached at the HNT's surface can form hot spots between each other, where local electric fields from each pair of NPs are enhanced [11,12]. Moreover, plasmonic NPs, which are fixed on HNTs, are protected from sticking together, they form agglomerates less often, and retain their properties longer [11].…”

“…NPs of plasmonic metals attached at the HNT's surface can form hot spots between each other, where local electric fields from each pair of NPs are enhanced [11,12]. Moreover, plasmonic NPs, which are fixed on HNTs, are protected from sticking together, they form agglomerates less often, and retain their properties longer [11]. Note that the physical properties of nanostructures depend on their topology-driven interface conditions, and an example of the terahertz light absorption in semiconductor nanoshells resonantly enhanced due to the strong coupling between interface plasmons and phonons is demonstrated [13].…”

“…The SERS phenomenon can also allow using such NPs in the solar energy conversion systems [20] and as biosensors for the detection of different substances both in water and in vitro [17,21]. Ag-NPs deposited on the HNTs surface can result in localized surface plasmon resonance (LSPR) in the region of 400 to 600 nm [11,22] and thus it could be used for SERS [3]. It was shown that a noticeable SERS response is observed upon the addition of Rhodamine 6G dye to the HNTs:Ag-NPs nanocomposite [11].…”

“…Ag-NPs deposited on the HNTs surface can result in localized surface plasmon resonance (LSPR) in the region of 400 to 600 nm [11,22] and thus it could be used for SERS [3]. It was shown that a noticeable SERS response is observed upon the addition of Rhodamine 6G dye to the HNTs:Ag-NPs nanocomposite [11]. Note, the SERS activity of HNTs:Ag-NPs persists even after soaking in aqueous solution for a week [11].…”

“…It was shown that a noticeable SERS response is observed upon the addition of Rhodamine 6G dye to the HNTs:Ag-NPs nanocomposite [11]. Note, the SERS activity of HNTs:Ag-NPs persists even after soaking in aqueous solution for a week [11]. While Ag-NPs have a wide range of applications in disinfection [14], the possibility of their deposition on the HNT's matrix makes it possible to enhance the effect by combining the bactericidal action of silver ions with electric field amplification from LSPR modes [22].…”