| Apr 26, 2023 |
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(Nanowerk News) Smartphones could one day become portable quantum sensors thanks to a new chip-scale approach that uses organic light-emitting diodes (OLEDs) to image magnetic fields.
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Researchers from the ARC Centre of Excellence in Exciton Science at UNSW Sydney have demonstrated that OLEDs, a type of semiconductor material commonly found in flat-screen televisions, smartphone screens and other digital displays, can be used to map magnetic fields using magnetic resonance.
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Sensing of magnetic fields has important applications in scientific research, industry and medicine.
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Published in the journal Nature Communications (“Sub-micron spin-based magnetic field imaging with an organic light emitting diode”), this technique is able to function at microchip scale and – unlike other common approaches – does not require input from a laser.
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| An illustration of the spatially-resolved ODMR (optically detected magnetic resonance) system for magnetic field imaging. (Image: ARC Centre of Excellence in Exciton Science)
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The majority of existing quantum sensing and magnetic field imaging equipment is relatively large and expensive, requiring either optical pumping (from a high-powered laser) or very low cryogenic temperatures. This limits the device integration potential and commercial scalability of such approaches.
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By contrast, the OLED sensing device prototyped in this work would ultimately be small, flexible and mass-producible.
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The techniques involved in achieving this are electrically detected magnetic resonance (EDMR) and optically detected magnetic resonance (ODMR). This is achieved using a camera and microwave electronics to optically detect magnetic resonance, the same physics which enables Magnetic Resonance Imaging (MRI).
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Using OLEDs for EDMR and ODMR depends on correctly harnessing the spin behaviour of electrons when they are in proximity to magnetic fields.
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OLEDs, which are highly sensitive to magnetic fields, are already found in mass-produced electronics like televisions and smartphones, making them an attractive prospect for commercial development in new technologies.
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Professor Dane McCamey of UNSW, who is also an Exciton Science Chief Investigator, said: “Our device is designed to be compatible with commercially available OLED technologies, providing the unique ability to map magnetic field over a large area or even a curved surface.
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“You could imagine using this technology being added to smartphones to help with remote medical diagnostics, or identifying defects in materials.”
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First author Dr Rugang Geng of UNSW and Exciton Science added: “While our study demonstrates a clear technology pathway, more work will be required to increase the sensitivity and readout times.”
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Professor McCamey said that a patent has been filed (Australian Patent Application 2022901738) with a view toward potential commercialisation of the technology.
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