Fabrication, Properties And Applications Of 3D Aluminum Hybrid Plasmonic Nanostructures With Large Areas

Plasmonic materials with large area,high-density "hot spots"(high electric field intensity)are very important for achieving ultra-high sensitivity molecular detection and high efficiency solar energy conversion.Therefore,the research of non-noble metal plasmonic materials with low cost and abundant reserves is of great theoretical and practical significance for practical application.In this paper,a novel three-dimensional hybrid aluminum nanostructure(3D-Al-HNS)with large area and high-density "hot spot" was prepared by a simple laser direct writing technique in liquid-nitrogen.It consists of three-dimensional hybrid aluminum nanoparticles and each 3D-Al-HNS is self-assembled on large particles by several small particles.Numerical simulations show that the thin oxide layer between adjacent particles in each hybrid structure can excite strong plasmon coupling to form a "hot spot",and the coupling between small particles and large particles is more intense.The enhancement of electric field outside the oxide layer is obviously higher than other aluminum nanostructures reported in the literature.In addition,three-dimensional stacking of hybrid structures can further increase the "hot spot" density.The localized surface plasmon resonance of this three-dimensional hybrid structure results in plasmon-enhanced light trapping from deep ultraviolet to visible broad band and has long-term stability.Furthermore,this material was used as a substrate for surface enhanced Raman spectroscopy(SERS)and used for the detection of crystal violet molecules.The results show that the enhancement factor is three orders of magnitude higher than that reported for aluminum nanomaterials,and the detection limit and SERS enhancement factor for nonresonant molecules have reached the noble metal level.At the same time,the substrate has a stability of up to six months,and can be reused many times.In summary,this high-performance,inexpensive plasmonic material has a broad application prospect in biosensors and solar energy conversion based on plasmonics enhancement.