Metal-Free, Graphene Oxide-Based Tunable Soliton and Plasmon Engineering for Biosensing Applications

Abstract

The quest for auxiliary plasmonic materials with lossless properties began in the past decade. In the current study, a unique plasmonic response is demonstrated from a stratified high refractive index (HRI)–graphene oxide (GO) and low refractive index (LRI)–polymethyl methacrylate (PMMA) multistack. Graphene oxide plasmon-coupled emission (GraPE) reveals the existence of strong surface states on the terminating layer of the photonic crystal (PC) framework. The chemical defects in GO thin film are conducive for unraveling plasmon hybridization within and across the multistack. We have achieved a unique assortment of metal-dielectric-metal (MDM) ensuing a zero-normal steering emission on account of solitons as well as directional GraPE. This has been theoretically established and experimentally demonstrated with a metal-free design. The angle-dependent reflectivity plots, electric field energy (EFI) profiles, and finite-difference time-domain (FDTD) analysis from the simulations strongly support plasmonic modes with giant Purcell factors (PFs). The architecture presented prospects for the replacement of metal-dependent MDM and surface plasmon-coupled emission (SPCE) technology with low cost, easy to fabricate, tunable soliton [graphene oxide plasmon-coupled soliton emission (GraSE)], and plasmon [GraPE] engineering for diverse biosensing applications. The superiority of the GraPE platform for achieving 1.95 pg mL–1 limit of detection of human IFN-γ is validated experimentally. A variety of nanoparticles encompassing metals, intermetallics, rare-earth, and low-dimensional carbon–plasmonic hybrids were used to comprehend PF and cavity hot-spot contribution resulting in 900-fold fluorescence emission enhancements on a lossless substrate, thereby opening the door to unique light–matter interactions for next-gen plasmonic and biomedical technologies.

Plasmon-Coupled Directional Emission from Soluplus-Mediated AgAu Nanoparticles for Attomolar Sensing Using a Smartphone

“…While the surface enhanced resonance Raman scattering (SERRS) platform supported by Ag nanowires as a plasmonic substrate could lower the detection limit to nanomolar levels, 65 our earlier work using the SPCE platform lowered the detection limit to 0.1 picomolar concentrations using AgCD (silver decorated carbon dots) as efficient nanoantennas in the SPCE platform. 18 Nevertheless, there are no reports that discuss further lowering this detection limit. In this context, we have engineered the ext.…”

“…7−11 The near-field optical confinement provided by the plasmonic NPs generate regions of intense EM "hotspots", when coated on a metal thin film. 16,17 Although a variety of NPs including low-dimensional materials, 18 self-assembled soret colloids, 7 and intermetallics 19,20 have been studied for their photoplasmonic contribution to SPCE, physicochemical evaluation of gold (Au) NPs has been inadequate on account of inevitable quenching of fluorophores located in distances <5 nm. In comparison to other coinage NPs (Ag, Pt, Pd), AuNPs exhibit manifold functionalities due to high stability with precise geometries, extraordinary optoelectronic properties, superior biocompatibility, tunable biophysicochemical properties and ability for multifunctionalization with inorganic/ biological/organic ligands.…”

“…Recently, research efforts have been devoted to synergize PEF and SPCE into a single hybrid platform. − , Generally, the enhancement factor of SPCE substrate is 5–10-fold as compared to traditional luminescence. − , Lakowicz and co-workers have demonstrated the significance of silver (Ag) NPs spacer layer engineering on SPCE platform to further augment the enhancement to 60-fold . With this as a preliminary step for combining PEF and SPCE, diverse nanoarchitectures have been explored to further augment the SPCE enhancements. − The near-field optical confinement provided by the plasmonic NPs generate regions of intense EM “hotspots”, when coated on a metal thin film. , Although a variety of NPs including low-dimensional materials, self-assembled soret colloids, and intermetallics , have been studied for their photoplasmonic contribution to SPCE, physicochemical evaluation of gold (Au) NPs has been inadequate on account of inevitable quenching of fluorophores located in distances <5 nm. In comparison to other coinage NPs (Ag, Pt, Pd), AuNPs exhibit manifold functionalities due to high stability with precise geometries, extraordinary optoelectronic properties, superior biocompatibility, tunable biophysicochemical properties and ability for multifunctionalization with inorganic/biological/organic ligands .…”

Photonic and Plasmonic Metasensors

“…Aside from the discussed studies, in 2021, Ramamurthy's group [324] engineered a metal-free plasmonic Tamm-resonant metastructure based on a combination of high refractive index graphene-oxide and low refractive index PMMA layers (Figure 10j). From the technical standpoint, it is demonstrated that the realized graphene-oxide plasmon-coupled emission (GraPE) exhibits the presence of robust surface resonances on the terminating layer of the tailored configuration, in which pronounced plasmon hybridization took place across the PMMA stack owing to the chemical defects in the graphene oxide monolayer.…”

“…The insets in each panel represent a linear relationship in bilogarithmic coordinates. j-n) Reproduced with permission [324]. Copyright 2021, American Chemical Society.…”