Light-Programmed Bistate Colloidal Actuation Based on Photothermal Active Plasmonic Substrate

Photothermophoretic Splitting of Gold Nanoparticles for Plasmonic Nanopores and Nanonets Sensing

Optical processing of single plasmonic nanoparticles reinvents the way of high-density information storage, high-performance sensing, and high-definition displays. However, such laser-fabricated nanoplasmonics with well-defined hot spots remain elusive due to the diffraction limit of light. Here we show Au nanoparticle (NP) decorated nanopores can be facilely generated with photothermal splitting of single Au NPs embedded in a silica matrix. The extremely high local temperature induced by plasmonic heating renders gradients of the temperature and surface tension around the Au NP, which drives the nanoscale thermophoretic and Marangoni flow of molten Au/silica. As a result, a nanopore decorated with fragmented Au NPs is formed in the silica film, which presents much stronger surface-enhanced Raman scattering as compared to a single Au NP due to the emergence of hot spots. This strategy can be used to generate plasmonic nanopores of various sizes in the silicon nitride (SiNx) films, which further transforms into nanonets at ambient conditions via light-induced reconstruction of silicon nitride membrane. These nanonets can serve as a robust platform for single particle trapping and analysis.

In Situ Nanomechanics: Opportunities Based on Superplastic Nanomolding

In situ nanomechanics, referring to the real-time monitoring of nanomechanical deformation during quantitative mechanical testing, is a key technology for understanding the physical and mechanical properties of nanoscale materials. This perspective reviews the progress of in situ nanomechanics from the aspects of preparation and testing of nanosamples, with a major focus on one-dimensional (1D) nanostructures and discussions of their challenges. We highlight the opportunities provided by in situ nanomechanics combined with the superplastic nanomolding technique, especially in the aspects of regulating physical and chemical properties which are highly exploitable for mechanoelectronics, mechanoluminescence, piezoelectronics, piezomagnetism, piezothermography, and mechanochemistry.