New OLED Technology Able to Image Magnetic Fields

Tuesday - May 2 2023, 14:12 UTC - 1 year ago

Australian researchers have developed an OLED-based sensor, allowing it to be utilized as a portable quantum sensor to image magnetic fields. It has a field sensitivity of ~160 µT Hz−1/2 µm−2, eliminating the need for MRI and having potential application in healthcare and industrial sectors.

OLEDs are one of the best display technologies in television and phones. They are super light and give out a colorful and brighter picture. They can even be wrapped around your waist.

And now, scientists in Australia claim that the OLEDs in our phones and TVs could one day be used as portable quantum sensors to image magnetic fields.

The new device architecture, developed by researchers at UNSW Sydney, allows one to measure the magnetic field electrically and optically without using lasers.

"Our findings show that OLEDs, a commercially available technology, can be used not only for displays and lighting but also for quantum sensing and magnetic field imaging by integrating a small piece of microwave electronics," says the study's first author, Dr. Rugang Geng.

"If this technology is properly developed, people could simply use their smartphones to map the magnetic fields around them, for example, to spot defects in diamonds or jewelry. This also has applications in industry, such as finding defects in construction materials or as a biomedical sensor." .

--- The device could have important implications in healthcare and industrial sectors --- .

Dr. Geng explains the basic working principle of an OLED device: "...when a voltage is applied, electrons and holes are injected into different layers of the device. When the electrons and holes meet in the central layer, they form ‘excitons’, which emit visible light when they decay, and that’s what makes OLEDs useful as displays and lighting sources." .

In the press release, the team explains that light emission via an OLED exploits the charge characteristics of electrons, which have a negative charge, and holes, which have a positive charge. They both also have another intrinsic property called spin. Sensitive to external magnetic fields, the spin can flip-flop or switch its direction under magnetic resonance conditions.

"By measuring the signal change, both in electric current and emission light, induced by such a flip-flop, we are able to detect the strength of any magnetic field the device is exposed to," says Dr. Geng.

By integrating an OLED with a microwave resonator, the team made a small oscillating magnetic field across the OLED device, allowing each pixel of the OLED screen to act as a small magnetic field sensor.

The device uses a camera and microwave electronics to detect magnetic waves, the same method that also enables Magnetic Resonance Imaging (MRI).

The device has potential application in healthcare and industrial sectors, as it could accurately detect magnetic waves, eliminating the need for MRI.

With this technology, people could use their smartphones to map out magnetic fields to spot defects in jewelry or construction materials. Portable quantum sensors could also have wide applications across different sectors and be of great importance to the future of these industries.