image: Representative laser operations and application outcomes from laser induced fluorescence functionalization of nanomaterials. Schematic abstract of review layout. Left. Representative laser techniques discussed in the review, comprising laser driven synthesis of nanostructures from thermal ablation of precursors in solutions, laser direct writing through laser initiated redox or combustion at nanomaterial surface, and spatial patterning of nanomaterials through optical gradient and radiation forces at the laser beam waist. Right. Corresponding outcomes from the various laser processes, including the formation of diverse range of fluorescent nanomaterials with refined control in composition and dimensions, and spatially refined surface modifications that result in superior color tunability and micropatterning. view more
Credit: by Eng Tuan Poh, Sharon Xiaodai Lim, Chorng Haur Sow
The extensive lineage of laser-based operations has presented substantial contribution to the production, modification, and patterning of various nanomaterial systems. In particular, with the broad infiltration of fluorescent nanomaterials into many niche applications (bio-tagging, micro-encryption, photonics), the ease to alter fluorescence properties with a focused laser presents immense opportunity to research efforts in material science and physics.
In a new publication in Light: Advanced Manufacturing, a team of scientists led by Professor Chorng Haur Sow from the Nanomaterials Laboratory in the Department of Physics, National University of Singapore reviewed the key influence of various laser-based techniques upon the fluorescence properties across a plethora of nanomaterials. Bridging laser operations to fluorescent nanomaterials, the review spans a wide range of laser techniques including direct laser writing, laser ablation, microprinting and hybrid patterning, coupled to the corresponding fluorescent nano-systems utilizing defect or dopants-based emission and redox-induced fluorescent states.
Beginning with a segment on laser-induced fluorescence, they evaluated laser-assisted control in fluorescence properties at the nanomaterial production stage. With the involvement of the laser’s photonic input at the material synthesis process, the control in nanomaterial composition and dimension provided versatile tunability in the fluorescence colors of the synthesized nanomaterials. Beyond, they also introduced nanomaterials with fluorescence that can be activated from laser post-modifications, producing compositional changes and defects as origins to the initiated fluorescence. Together, the section focused upon instances where the laser converts non-fluorescing precursors to fluorescent forms.
With nanomaterials originally imbued with fluorescent traits, the subsequent sections of the review explore examples where the laser alters either the fluorescence features or spatial resolution of the emitting nanomaterial. Using the laser as an optimal handle to fine-tune the nanomaterials’ emission colors and spectra, the capability for on-demand, high resolution adjustments of the material fluorescence post-synthesis confers great potential in understanding the nanomaterial chemistry and exciton physics at work. Furthermore, with laser refined spatial resolution in the emplacement of fluorescent nanomaterials, quality micropatterns and encryption technologies can be furnished with high color and spatial quality.
Segmented into three main sections of laser induced fluorescence, laser modified fluorescence and laser assisted patterning, the review covers an expansive range of state-of-the-art laser technologies applied to a plethora of nanomaterial variants, each with its distinct fluorescence origins. In light of that, the scientists are confident that “the ever-increasing attention on the convenience of laser tuning of nanomaterial properties would favor the timely delivery of this review as a holistic summary that would prompt the next generation of laser operations for advanced functional nanomaterials.”
When assessing the value of lasers in the advancement of materials engineering and fluorescence photophysics, they added “with the focused laser beam, we can induce localized, microscale reactions that unravel intriguing physics phenomena with extensive engineering control over the nanomaterial performance. This allows enhanced mastery over desirable material properties while unlocking greater scientific understanding over the exotic mechanisms at work.”
Journal
Light: Advanced Manufacturing