Researchers at the University of Michigan have developed an innovative type of organic light-emitting diode (OLED) that is both lightweight and compact.
The research team claims that the new OLED device can convert near-infrared light into visible light while amplifying it over 100 times. Unlike traditional night vision systems, which rely on bulky image intensifiers to convert near-infrared light into visible light, this new approach eliminates the need for high voltage and cumbersome vacuum layers. Current systems utilize image intensifiers that transform incoming near-infrared light into electrons, which then accelerate through a vacuum into a thin disc filled with tiny channels, resulting in an amplification of 10,000 times.
Chris Giebink, a professor of electrical and computer engineering and physics at U-M said: “That’s much thinner than a strand of hair, which is about 50 microns thick.” This significant reduction in thickness could lead to lower power consumption and extended battery life, as the device operates at much lower voltages compared to traditional systems.
The innovative design integrates a photon-absorbing layer that converts infrared light into electrons and features a five-layer OLED stack, where these electrons are transformed into visible light photons. For every electron passing through the OLED stack, ideally, five photons are produced. Some of these photons are emitted to the user’s eye, while others are reabsorbed, creating a feedback loop that amplifies the output light.
“This marks the first demonstration of high photon gain in a thin film device,” stated, Raju Lampande, a postdoctoral research fellow and lead author of the study. Furthermore, the device displays a unique memory behavior, known as hysteresis, which could have implications for computer vision systems.
“This device can get stuck on and remember things over time, which is unusual,” Giebink explained.