Plasmonic-Thermoelectric Nanotweezers for Immersive SERS Mapping

Abstract

Surface-enhanced Raman spectroscopy (SERS) technology usually uses metallic nanoparticles to enhance Raman scattering signals, thereby significantly adding to molecule-level recognition and detection. However, realization of nanometer-scaled SERS imaging in liquid environments is extremely difficult due to the requirements of both precise scanning of single metallic nanoparticle and high enhancement field and thus has never been achieved before. To overcome this obstacle, we demonstrate an immersive nanometer-scaled SERS mapping technology, based on dynamic scanning of a single metallic nanoparticle with a plasmonic-thermoelectric nanotweezers system. The technology offers greater stability in the plasmonic trapping of gold nanoparticles at relative low power, as well as generating higher electric fields in the gap region. Through its dynamics, two-dimensional nanometer-scaled SERS imaging is achieved successfully. In regard to in liquid environments, this technology provides a mapping method for label-free imaging of ultrathin materials, structures, and biological samples.

Colloidal Manipulation through Plasmonic and Non‐plasmonic Laser‐Assisted Heating

“…Yuan and his group demonstrated an immersive nanometer‐scaled SERS mapping technology in a liquid environment with a combination of plasmonic and thermoelectric technology called plasmonic‐thermoelectric tweezers (PTT). [ 135 ] The introduction of CTAC into the gold nanoparticle (100 nm) solution creates a thermoelectric field when the gold film (35 nm) is excited with a 532 nm laser and thereby stably traps the nanoparticle at the hot zone at relatively low power (0.5 mW) ( Figure a). The trapped nanoparticle generates a nanosized hot spot in the gap (5 nm) between the particle and film.…”

“…g) CorrespondingRaman spectra at the gold nanoparticle trapping location. Reproduced with permission [135]. Copyright 2022, American Chemical Society.…”

Casting liquid PDMS on self-assembled bilayer polystyrene nanospheres to prepare a SERS substrate with two layers of nanopits for detection of p-nitrophenol

“…Surface-enhanced Raman spectroscopy (SERS) is a fast, sensitive, and robust analysis tool with simple data processing for real-time, in situ trace detection. It can provide rich chemical information and is widely applied in materials science, [1][2][3] environmental protection, [4][5][6] food safety, [7][8][9] medicine, [10][11][12] and public safety. 13,14 The SERS enhancement mechanisms are mostly attributed to the electromagnetic enhancement (EM) effects and chemical enhancement (CE) effects.…”

Thermoelectrically Driven Dual-Mechanism Regulation on SERS and Application Potential for Rapid Detection of SARS-CoV-2 Viruses and Microplastics

“…The principle of CM is based on the charge transfer between the substrate and the probe molecule, resulting in a change in the polarization rate of the molecule. , 2D materials can undergo charge transfer with probe molecules under photoexcitation, whereas noble metal NPs under photoexcitation can generate strong electromagnetic fields. Therefore, noble metal NP-2D materials that can combine CM and EM have been extensively investigated, such as Ag/Au–ZnO, , Ag/Ag–GaN, Ag/Au–graphene, Ag/Ag–Fe 3 O 4 , and Ag/Ag–MoS 2 . The above substrates exhibit ultrahigh sensitivity on molecular detection.…”

“…Therefore, noble metal NP-2D materials that can combine CM and EM have been extensively investigated, such as Ag/Au− ZnO, 10,11 Ag/Ag−GaN, 12 Ag/Au−graphene, 13 Ag/Ag− Fe 3 O 4 , 14 and Ag/Ag−MoS 2 . 2 The above substrates exhibit ultrahigh sensitivity on molecular detection. However, CM has less contribution than EM in terms of providing sensitivity.…”