New organic LED breaks through data speed

Yin Te Electronics: Industry Push

Researchers are using a new type of organic LED to break through the limits of data speed.

The domain provides' practically 'unlimited bandwidth (>400 THz). Among these systems, visible light communication (VLC) is attractive because it has the potential to utilize light-emitting devices that have been widely used in commercial applications ranging from lighting systems to mobile phones and television displays.

In the fastest VLC link reported so far, the light emitter consists of a light emitting diode (LED) and a laser diode (LD), which use inorganic semiconductors (usually gallium nitride) as the emission medium and have high light output power and wide bandwidth. These characteristics make inorganic LEDs and LDs suitable for integration into dual-purpose lighting devices that can provide both white lighting and data transmission simultaneously. However, the use of organic light-emitting diodes (OLEDs) is an effective alternative, which has attracted great attention for VLC. People's interest in OLEDs used for communication is not only driven by their widespread use in display technology, but also by the same advantages of successful organic electronics technology. Importantly, organic semiconductors can be deposited over large areas inexpensively through thermal evaporation or spin coating, scraping, inkjet, or spray coating solutions. Large area organic semiconductor (OS) lighting devices have entered the market and are expected to become the next large-scale application of OS after OLED (AMOLED) displays.

Visible light communication (VLC) is a wireless technology that relies on light intensity modulation and may change the connectivity of the Internet of Things (IoT). However, the low penetration depth of visible light in non transparent media hinders VLC. One solution is to extend the operation to the "near (non) visible" near-infrared (NIR, 700-1000nm) region, extending the spectral range to the near-infrared (NIR, 700-1000nm) not only expands the bandwidth of the VLC link, but also paves the way for its integration into many applications that utilize NIR radiation. Near infrared emission devices are used in several different fields, including safety, biological detection, and photodynamic/photothermal therapy, both of which benefit from the semi transparency of biological tissues in this spectral window. In the case of wearable or implantable biosensors, NIR photons can be used to monitor human vital signs and communicate wirelessly with other devices.

Scientists have created new OLEDs processed with far red/near-infrared solutions. By integrating the device into a real-time VLC device, as shown in Figure 1a, an error free transmission speed of over 1Mb/s has been achieved. Successfully expanded bandwidth and achieved the fastest data speed ever for organic light-emitting diodes.

The new OLED has been described in the journal "Light Science and Applications", creating opportunities for new Internet of Things (IoT) connectivity and wearable and implantable biosensor technologies.

This project is a collaboration between Newcastle University, University College London, London Centre for Nanotechnology, Institute of Organic Chemistry of the Polish Academy of Sciences (Warsaw, Poland), and National Research Council Institute for Nanostructured Materials (CNR-ISMN, Bologna, Italy).

From the perspective of IoT applications, the data rate achieved by the team through this groundbreaking device is sufficient to support indoor point-to-point links.

The researchers emphasized the possibility of achieving this data rate without the need for computationally complex and power demanding equalizers. Due to the absence of toxic heavy metals in the active layer of organic light-emitting diodes, the new VLC device is expected to integrate portable, wearable, or implantable organic biosensors.