Nanopillars – A State-of-the-art Optical Sensor
November 8, 2016 | DTUEstimated reading time: 2 minutes
Reliable, cheap and quick recognition of molecules at challenging concentrations of ~1 ppb (parts per billion) or less is now possible thanks to a sensor developed at DTU Nanotech.
Potential analytes include toxic food additives, chemical warfare agents, hazardous building materials and human disease markers.
The sensor consists of nanopillars with heights of 600 – 800 nm. These pillars are able to enhance significantly the spectroscopic fingerprints of the target molecules nearby, making them distinguishable at ultra-low concentrations. The technique is called surface-enhanced Raman spectroscopy (SERS).
Postdoc Kaiyu Wu from DTU Nanotech says that “an ideal sensor for SERS should exhibit reproducibly high enhancement over macroscopic areas and be cost effective. It is extremely difficult to fulfil both.”
The nanopillar sensor is among the very few throughout the world known to achieve both standards.
Just like ‘pixels’
“Hot spots are the key elements in a SERS sensor, as they resolve the spectroscopic fingerprints of the target molecules. They are like pixels in a display that resolve different parts of an image. However, hot spots cannot be seen with the naked eye since their dimensions are only several to tens of nanometers”, says Kaiyu Wu.
The initial nanofabrication process of the nanopillar sensors was developed by Senior Researcher Michael Stenbæk Schmidt at DTU Nanotech. The process does not require any lengthy and expensive lithographic steps, thus it provides possibilities for the produced nanopillars to be used as cheap and expendable consumables.
The aim of Kaiyu Wu’s PhD project, which finished recently in June 2016, was to engineer ‘pixels’, i.e. hot spots in the nanopillars in order to take their sensing performance to the next level. This goal was achieved with the help of advanced spectroscopic and theoretical tools, as well as state-of-the-art nanofabrication techniques at DTU Nanotech and DTU Danchip.
The improved sensors now possess high-quality, high-density and reproducible nanoscale hot spots over macroscopic areas, as well as enhancement factors ultimately eclipsing the 100 million mark for molecular fingerprints.
The nanopillar sensors can be easily paired with portable read-out systems to enable on-site detection of analytes. Furthermore, their high-quality and high-density hot spots guarantee an extra-high sensitivity which reduces the time of detection to just several seconds for regular targets.
Kaiyu Wu’s research is part of the ‘NAPLAS – NAnoPLAsmonic Sensors’ project funded by The Danish Council for Independent Research, and the ‘HERMES – High Exponential Rise in Miniaturized cantilever-like Sensing’ project funded by the European Research Council.
Suggested Items
Altair Acquires Research in Flight, Forging a New Path for Aerodynamic Analysis
05/03/2024 | AltairAltair a global leader in computational intelligence, announced it has acquired Research in Flight, maker of FlightStream®, which provides computational fluid dynamics (CFD) software with a large footprint in the aerospace and defense sector and a growing presence in marine, energy, turbomachinery, and automotive applications.
Intel Takes Next Step Toward Building Scalable Silicon-Based Quantum Processors
05/02/2024 | BUSINESS WIRENature published an Intel research paper, “Probing single electrons across 300-mm spin qubit wafers,” demonstrating state-of-the-art uniformity, fidelity and measurement statistics of spin qubits.
Argonne, Toyota Collaborate on Cutting-Edge Battery Recycling Process
05/01/2024 | BUSINESS WIREThe U.S. Department of Energy’s (DOE) Argonne National Laboratory has recently launched a collaboration with Toyota Motor North America that could reduce the nation’s reliance on foreign sources of battery materials.
Chinese Smartphone Market Maintains its Recovery Momentum at 6.5% Growth in 1Q24,
04/26/2024 | IDCAccording to preliminary data from the International Data Corporation (IDC) Worldwide Quarterly Mobile Phone Tracker, China smartphone shipments grew 6.5% year over year (YoY) to 69.3 million units in 1Q24.
Boeing Opens Research & Technology Center in Japan
04/23/2024 | BoeingBoeing today opened a Boeing Research & Technology (BR&T) Center in Japan that will focus on innovation to enable the commercial aviation industry meet its goal of net zero carbon emissions by 2050.