The interest in OLEDs for communication is driven not only by their widespread use in display technologies but also by the very same advantages that have been driving the success of organic electronics. However, the use of organic light-emitting diodes (OLEDs) represents a valid alternative, which is gaining considerable attention for VLC 9, 10, 11, 12, 13, 14. These properties make inorganic LEDs 1, 2 and LDs 7, 8 suitable for integration into dual-purpose luminaires capable of simultaneously providing white lighting and data transmission. In the fastest VLC links reported thus far, the optical transmitters consist of light-emitting diodes (LEDs) 3 and laser diodes (LDs) 4, 5, 6 featuring an inorganic semiconductor (typically gallium nitride) as the emissive medium, which affords high optical output power and broad bandwidth.
Among these systems, VLC systems 2 are appealing because of the possibility of leveraging the ubiquity of the light-emitting devices already used in countless commercial applications, ranging from lighting systems to mobile phones and TV displays. In recent years, the increasing demand for faster data transmission speeds has shifted the attention of researchers from bandwidth-limited radio technologies to optical wireless communication systems 1, which offer “practically” unlimited bandwidth (>400 THz) by exploiting the ultraviolet to infrared region of the electromagnetic spectrum. These are the highest rates ever reported for an online unequalised VLC link based on solution-processed OLEDs. With these OLEDs, we then demonstrate a “ real-time” VLC setup achieving a data rate of 2.2 Mb/s, which satisfies the requirements for IoT and biosensing applications. Here, we report new far-red/NIR organic light-emitting diodes (OLEDs) with a 650–800 nm emission range and external quantum efficiencies among the highest reported in this spectral range (>2.7%, with maximum radiance and luminance of 3.5 mW/cm 2 and 260 cd/m 2, respectively). One solution is to extend operation into the “nearly (in)visible” near-infrared (NIR, 700–1000 nm) region, thus also enabling VLC in photonic bio-applications, considering the biological tissue NIR semitransparency, while conveniently retaining vestigial red emission to help check the link operativity by simple eye inspection. However, VLC is hindered by the low penetration depth of visible light in non-transparent media.
Visible light communication (VLC) is a wireless technology that relies on optical intensity modulation and is potentially a game changer for internet-of-things (IoT) connectivity.
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