Earth Abundant Iron-Rich N-Doped Graphene Based Spacer and Cavity Materials for Surface Plasmon-Coupled Emission Enhancements

Abstract

We demonstrate for the first time the use of Fe-based nanoparticles on N-doped graphene as spacer and cavity materials and study their plasmonic effect on the spontaneous emission of a radiating dipole. Fe-C-MF was produced by pyrolizing FeOOH and melamine formaldehyde precursor on graphene, while Fe-C-PH was produced by pyrolizing the Fe-phenanthroline complex on graphene. The use of the Fe-C-MF composite consisting of Fe-rich crystalline phases supported on N-doped graphene presented a spacer material with 116-fold fluorescence enhancements. On the other hand, the Fe-C-PH/Ag based cavity resulted in an 82-fold enhancement in Surface Plasmon-Coupled Emission (SPCE), with high directionality and polarization of Rhodamine 6G (Rh6G) emission owing to Casimir and Purcell effects. The use of a mobile phone as a cost-effective fluorescence detection device in the present work opens up a flexible perspective for the study of different nanomaterials as tunable substrates in cavity mode and spacer applications.

Wood Microfluidics

“…In SPCE, the fluorophore of interest is dispersed within a polymer that is either spin-coated or adsorbed on to a silver thin film substrate. 17 The fluorophore is then irradiated with the corresponding excitation source either in Kretschmann or reverse Kretschmann configuration resulting in the coupling of fluorescence with the silver surface plasmons. This leads to directional and enhanced emission.…”

“…We were able to produce different device designs, such as T-/Y-channel mixers, single channels capable of bearing a fluid path for surface plasmon-coupled enhanced (SPCE) fluorescence and detection of microbial contamination using resazurin. A primary focus for this manuscript was to demonstrate the use of POC wood chips for protein detection via SPCE. − SPCE has gained a lot of attention in the past decade because of its ability to address inherent drawbacks of conventional fluorescence particularly when the fluorophore has a low quantum yield. Fluorescence based detection has hugely impacted the current generation of biomedical, diagnostic and sensing devices .…”

“…Despite its multiple advantages and applications, there are intrinsic drawbacks like: low collection efficiency owing to isotropic emission, poor resolution of emission from multiple analytes and low sensitivity. Researchers across the globe have discovered new methods to overcome these drawbacks and have provided better fluorescent enhancement techniques that exploit the properties of nanoplasmonics. − In SPCE, the fluorophore of interest is dispersed within a polymer that is either spin coated or adsorbed onto a silver thin film substrate. In previous work, we were able to detect a monomolecular layer of GFP using SPCE .…”

Ag‐CNT Architectures for Attomolar Dopamine Detection and 100‐Fold Fluorescence Enhancements with Cellphone‐Based Surface Plasmon‐Coupled Emission Platform

“…In this context, we have pioneered the engineering of spacer and cavity materials on SPCE substrate for tunable fluorescence enhancements. Our earlier work on one‐minute spacer engineering with metallic nanoparticles, low‐dimensional carbon substrates, bio‐spacers, magnetic graphene nanocomposites and ceramic nanomaterials for various applications such as femtomolar sensing of organic moiety and picomolar detection of cardiac biomarker has resulted in a significant breakthrough in the next‐gen plasmonics arena. Alternative spacers were reported to show low fluorescence enhancements compared to carbon and metal nanomaterials…”

Surface plasmon–coupled emission imaging for biological applications

“…However, there is a great demand to achieve higher sensitivity and selectivity with the rapid development of life science. Recently, a surface-enhanced fluorescence technique, referred to as surface plasmon-coupled emission (SPCE), has been widely investigated [7][8][9][10][11]. The high collection efficiency, due to the directed radiation, greatly improves the sensitivity of SPCE.…”