Abstract
The extensive exploration of the collective optical and thermal effects for localized surface plasmon resonance (LSPR)-coupled nanoassemblies has propelled much recent research and development in fields of photoacoustic (PA) imaging and photothermal (PT) therapy, while the rational design and proper engineering of these assemblies under quantitative guidance is still a highly challenging task. In this work, by utilizing the finite element analysis (FEA) method and taking gold nanochains as example, the authors quantitatively studied the coupling optical/thermal response of the nanoassemblies and the associated nonlinearly enhanced PA/PT effect. Results show that compared with their individuals, the strong electromagnetic/thermal coupling between the individuals of the nanoassemblies results in a several-time enhancement of the per-particle-weighted optical absorption, consequential thermal field enhancement, and initial PA pressure, resulting in nonlinearly amplified energy conversion from incident light to heat and PA waves. The dependence of the nonlinear PA/PT enhancement on the assembly chain length, the size of the individuals, the interparticle distance, and the size uniformity of the building blocks is quantitatively discussed. PA experiments on gold nanochains and gold nanospheres are performed to validate the proposition, and the experiments well silhouetted the theoretical discussion. This work paves the way for the rational construction and optimization of plasmonic nanoassemblies with improved PA/PT conversion efficiency.
Highlights
Subwavelength metallic nanoparticles have been intensively researched for the past decades in fields of energy conversion [1], optical sensing [2], and biomedicine [3], with a unique host of new properties that are notably distinct from their bulk metals [4,5]
The most striking character of these metallic nanoparticles is their unique optical abilities to support localized surface plasmon resonance (LSPR) that arises from the free electrons oscillations [6]
By utilizing the finite element analysis (FEA) method and taking the basic structured nanosphere-assembled gold nanochains (GNCs) as example, we quantitatively studied the self-assembling-amplified nonlinear optical and thermal responses of the strong LSPR-coupled nanoassemblies, where the quantitative temperature field distribution and the initial PA pressure were obtained
Summary
Subwavelength metallic nanoparticles have been intensively researched for the past decades in fields of energy conversion [1], optical sensing [2], and biomedicine [3], with a unique host of new properties that are notably distinct from their bulk metals [4,5]. When the metallic nanoparticles are illuminated by light with a wavelength much larger than the nanoparticle size, the high-density free electrons in the metal immediately respond to the external electromagnetic (EM) field and oscillate coherently at the same frequency as the incident light. This plasmon-medicated EM-nanoparticle interaction results in strong light scattering and local EM field enhancement in the vicinity of the nanoparticle surface, which has enabled a variety of applications such as LSPR-enhanced Raman spectroscopy and biological sensing [7,8,9]. Despite the considerable promising future of metallic nanoparticles and the wide application of plasmon-medicated nanoparticles in PA/PT fields, significant hurdles such as the limited ability to tune the interactions of EM with individual nanoparticles and to further improve their optical and thermal performance still remain
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
