Comparison of the plasmonic performances between lithographically fabricated and chemically grown gold nanorods

Abstract

Noble metal nanostructures, especially gold nanocrystals, have attracted intensive interest due to their rich plasmonic properties and enormous potential technological applications. The preparation process of gold nanocrystals can strongly affect their plasmonic properties and therefore their performances in various applications. Chemically synthesized colloidal gold nanocrystals are usually employed in biomedical fields, while lithographically fabricated ones are highly preferred for constructing optical meta-structures. A detailed careful comparison of the plasmonic performances between lithographical and chemical metal nanostructures is strongly desired for using them for different applications. Herein, we experimentally measured and quantitatively compared the plasmonic properties, including longitudinal localized surface plasmon wavelengths (LLSPWs) and plasmon peak widths, scattering intensities, and local electric field enhancements, of lithographically fabricated and chemically grown gold nanorods. The lithographical nanorods exhibit much weaker scattering, largely broadened spectral widths, and considerably reduced electric field enhancements. Electrodynamic simulations suggest that the reduction in the plasmonic performance of the lithographical nanorods is caused mainly by the use of an adhesive metal layer and slightly by their polycrystalline nature. Our quantitative comparison results will be very helpful in guiding the selection of proper types of metal nanostructures for targeted technological applications.

Infrared‐Responsive Colloidal Silver Nanorods for Surface‐Enhanced Infrared Absorption

“…It is clear that most of the previous experimental demonstrations of SEIRA have relied on physical fabrication techniques, the most typical among which is electron beam lithography. Compared to lithographically fabricated metal nanostructures, colloidal metal nanocrystals synthesized by wet‐chemistry methods possess several attractive advantages: low cost, facileness, scalability, better shape and size control, and the prominent plasmonic performances due to their single‐crystalline nature and the absence of an adhesive layer between metal nanocrystals and underlying substrates . In addition, colloidal metal nanocrystals show great potential in life and biomedical sciences .…”

Calculated thickness dependent plasmonic properties of gold nanobars in the visible to near-infrared light regime

“…These works show that plasmonic properties depend on size, shape, material, and dielectric environment [30,33]. Previous studies have investigated length [34], aspect ratio [35], polarization of incident light [36], and nanostructure fabrication method [37]. Various methods have been used to evaluate the plasmonic properties, such as discrete dipole approximation [38], quasistatic approximation [39], etc.…”

Continuous‐Gradient Plasmonic Nanostructures Fabricated by Evaporation on a Partially Exposed Rotating Substrate

“…The plasmonic properties of individual metal nanostructures therefore need to be finely tuned by optimizing their geometrical parameters. Different approaches have been explored to reach a high level of control on nanostructure preparations, including both bottom‐up wet‐chemistry growth and top‐down lithographic techniques . For instance, various combinatorial chemical and combinatorial materials syntheses have been developed to enable fine tuning of metal nanostructures .…”

“…For instance, various combinatorial chemical and combinatorial materials syntheses have been developed to enable fine tuning of metal nanostructures . Though effective, these techniques are not perfect and manufacturing uncertainties, for example linked to the finite resolution of lithography, material crystallinities, or interfacial bonding properties, can result in considerable deviations from the desired optical behavior. The preparation of specific structures therefore often requires sequential optimization processes that are repetitive, time‐consuming, and costly.…”