In a scientific breakthrough, Dr Sarina Sarina from the QUT Centre for Materials Science has used sunlight to power a targeted and reversible process for chemical reactions that could be used to capture and convert molecules from raw materials into ingredients for medicines, intermediates and other valuable products.
Molecules are 10,000 times smaller than a cell — too small for a mechanical tweezer to move.
Sarina’s research group has optimised a process called ‘plasmonic optical trapping’ — dubbed light tweezers — which uses visible light and nanoparticles to create a plasmonic optical force capable of moving molecules through a solution.
“Until now, it was believed that intense optical force could only be generated by lasers,” Sarina said.
“We discovered how to use low-intensity visible light to generate enough plasmonic optical force to move molecules by introducing metallic nanoparticles to the solution.”
Plasmonic optical force is created when gold, silver and copper nanoparticles absorb light and dissipate excess energy as an electromagnetic field strong enough to attract or repel molecules based on polarity — the positive and negative charge.
“We can target molecules of interest by their polarity strength and draw them to the catalyst surface, then convert them into important products of interest or remove them from the solution,” Sarina said
“This process lets us control a chemical reaction better and avoid by-products.”
“It is a greener process because photocatalysts accelerate a chemical reaction with light, not with fossil fuels.”
“Light-induced reactions are also about 1000 times faster than thermal processes in a solution with very low concentration of molecules in a solution, which means we see results in less time using less energy.”
Using the visible light spectrum, which accounts for 47 per cent of solar energy, is also what allows Sarina to tune the electromagnetic field to target specific molecules.
“Each molecule has a different polarity. Changing the lumens, the intensity of light, into the nanoparticle will change the strength of its plasmonic optical force — attracting different molecules by polar strength,” Sarina said.
“However, not all metal nanoparticles can work this way with light. Only gold, silver and copper have plasmonic properties.”
The full article can be found here on Medium.