Nd2O3-Ag Nanostructures for Plasmonic Biosensing, Antimicrobial, and Anticancer Applications

Green synthesis of nanomaterials with multifaceted applications in photonics as well as biomedical fields has remained a daunting challenge. Engineering multielement nanohybrid libraries with synergistic surface function-alities from dielectric and metallic nanocomponents using sustainable approaches is seldom reported. In this context, we demonstrate a 1 min, user-and eco-friendly, sunlight-based green synthesis of Nd2O3-Ag, dielectric-metal ferroplasmon nanohybrids with detailed elucidation of the mechanism. Chemical anchoring of plasmonic Ag on high refractive index (n = 1.94), rare-earth Nd2O3 nanorods (average aspect ratio: similar to 3) alleviates Ohmic losses without damping the plasmon resonances. Ferroplasmon-on-a-mirror (FPoM), an analogue to conventional nanoparticle-on-a-mirror (NPoM), is presented for efficient coupling of s-polarized light on account of magnetic flux modes supported by it. Apart from realization of room temperature ferromagnetism (RTFM) for nanophotonic applications, the judicious metal-nonmetal combination displayed excellent bactericidal, fungicidal, antioxidant, and anticancer properties, establishing a convergent "one health perspective" of engineered nanohybrids. Whereas the unconventional s-polarized plasmon-coupled emission obtained is utilized for sensing of food hazard Allura Red (limit of detection, LOD: 10 aM) in the FPoM platform, the p-polarized emission is used for 4-nitrophenol sensing (LOD: 100 fM). Excellent correlation between the exceptionally high Purcel l factor (of 6.5 x 105 for the composite nanohybrid Nd2O3-Ag-carbon dot-graphene oxide) from simulations and experimentally obtained plasmon-coupled >2000-fold fluorescence emission enhancements is demonstrated. The utility of the proposed sunlight-induced nanoengineering to generate a library of nanocomposites comprising dielectric, metal, and graphitic plasmons is presented. We believe that the proposed methodology to generate hybrid nanomaterials with intriguing FPoM interfaces would be utilized for transdisciplinary nanophotonics as well as biomedical sensing applications.