Synthesis Innovations and Applications of Dual Plasmonic Heteronanostructures: Fundamentals to Future Horizons

The burgeoning fascination for plasmonic nanomaterials has been stimulated by their emerging applications in energy, medicine, and several optoelectronic technologies. The plasmonic properties of nanomaterials are engineered by various parameters that primarily include architecture (size and shape), composition, and dielectricity of the local environment. The pursuit to innovate the distinctive physicochemical functionalities of plasmonic nanostructures is conceivably addressed by precisely engineered nanoheterostructures (NHCs) because of their compositional and structural versatility. Often, heterostructuring manifests strong light–matter interactions that translate into plasmon–plasmon resonance coupling effects, forming dual plasmonic heterostructures (DPHs). Such exquisite structural control down to the nanometer level requires detailed understanding, aptly designed guidelines, and synthetic tools. In this review, first a brief fundamental knowledge about surface plasmonic resonance is discussed and then a detailed understanding of the interference phenomenon arising due to heterostructuring two plasmonic nano-objects is presented. The synthesis, plasmonic features, and diverse applications of different DPHs, from metal–metal to metal–semiconductor, are discussed at length in this review. Building on the current status of plasmon coupling in semiconductor–semiconductor and other NHCs and their interfacial energy/charge transfer mechanisms, the final part of the review summarizes the topic by shedding light on the research niche that provides direction for future prospects.