Single-Molecule Nonresonant Wide-Field Surface-Enhanced Raman Scattering from Ferroelectrically Defined Au Nanoparticle Microarrays

Abstract

Single-molecule detection by surface-enhanced Raman scattering (SERS) is a powerful spectroscopic technique that is of interest for the sensor development field. An important aspect of optimizing the materials used in SERS-based sensors is the ability to have a high density of “hot spots” that enhance the SERS sensitivity to the single-molecule level. Photodeposition of gold (Au) nanoparticles through electric-field-directed self-assembly on a periodically proton-exchanged lithium niobate (PPELN) substrate provides conditions to form well-ordered microscale features consisting of closely packed Au nanoparticles. The resulting Au nanoparticle microstructure arrays (microarrays) are plasmon-active and support nonresonant single-molecule SERS at ultralow concentrations (<10 –9 –10 –13 M) with excitation power densities <1 × 10 –3 W cm –2 using wide-field imaging. The microarrays offer excellent SERS reproducibility, with an intensity variation of <7.5% across the substrate. As most biomarkers and molecules do not support resonance enhancement, this work demonstrates that PPELN is a suitable template for high-sensitivity, nonresonant sensing applications.

Photoinduced Enhanced Raman from Lithium Niobate on Insulator Template

“…The resultant localized surface plasmon resonances can result in SERS enhancement factors of >10 10 . The polarization-dependent photochemistry of LN, which can be tailored via domain engineering and chemical patterning, has been previously exploited to deposit metallic nanoparticles − for Raman-based sensing of molecules. ,, To date, such work has been focused mainly on bulk single-crystal LN . The use of LNOI to deposit metallic nanoparticles for SERS may offer additional Raman scattering enhancement pathways, for example, through refractive index contrast effects.…”

Hybrid composite based on conducting polymers and plasmonic nanomaterials applied to catalysis and sensing

“…In Raman spectroscopy, only approximately one in 10 6 photons converted into stokes scattering light producing a weak analytical signal intensity [5][6][7][8][9][10]. However, the use of nanostructured materials can increase the efficiency of Raman scattering through plasmonic enhancement to enable single-molecule Raman detection [11,12]. Modern material processing and characterization methods can produce nanomaterials, including metal nanostructures with a range of different geometries and properties [10,[13][14][15][16].…”

Rapid and label‐free identification of different cancer types based on surface‐enhanced Raman scattering profiles and multivariate statistical analysis

“…Non-labeled methods are always using the Au nanoparticle (AuNP) colloid, Ag nanoparticle colloid, Au-Ag nanoparticle, rough noble metal surfaces, microarrays, and related methods. [10][11][12] The immune labeled method is based on the antigen-antibody reaction and surface modifications, which are mostly determined by specific and targeted testing. 13 Compared with the labeled method, the label-free SERS is simple, sensitive, low cost, and easy operation.…”

“…Enhanced substrates are extensively used in the non‐labeled and labeled methods. Non‐labeled methods are always using the Au nanoparticle (AuNP) colloid, Ag nanoparticle colloid, Au–Ag nanoparticle, rough noble metal surfaces, microarrays, and related methods 10‐12 . The immune labeled method is based on the antigen‐antibody reaction and surface modifications, which are mostly determined by specific and targeted testing 13 .…”