Researchers at the US DoE's Ames Laboratory developed a near ultra-violet (UV) OLED device that can be used as an on-chip photosensor. They say that this is the first time that light can be captured and manipulated at around 400 nm - or near the invisible end of the spectrum.
The researchers envision a tiny chip that can act as a whole spectrometer - so it can measure the absorption or luminescence spectrum of anything that can absorb or emit light. There are many applications for such a sensor - for food safety, water quality, medical diagnosis and more. This near-UV OLED development is a step towards that goal.
The main advance in this new research is the application of optical microcavities that alter the behavior of light wavelengths. An array of tiny OLEDs with different kinds of microcavities means that multiple analyses and optical excitations can be performed on the same device.
Back in 2014, researchers at the Fraunhofer FEP Institute demonstrated new UV-emitting OLED devices that can be used as low-cost personal diagnostic devices.