Researchers from the King Abdullah University of Science and Technology (KAUST) have designed a system that uses an innovative color converter based on luminescent materials known as phosphors, which are commonly used in LED lights, and combines them with nanocrystals of perovskite. This system has achieved record bandwidth, providing a data transmission rate of 2Gbit per second.
The major achievements in this work are breaking the record for data communication using visible light and, even more impressively, producing white light with a very high color-rendering index of 89, by designing a special color converter based on hybrid perovskite nanocrystals. The work demonstrates white light as both a lighting source and a system for ultra-high-speed data communications.
Visible light communication (VLC) is frequently touted as one of the possible solutions to the increasing congestion of the radio spectrum, which struggles to comply with the growing demand for wireless data services. VLC uses visible light rather than radio waves for data transmission. It is based on the use of lasers or LEDs that look like traditional lights and transmit information by rapid flashing, imperceptible to the human eye. This flashing transmits a binary code to the receiver at a higher speed and with higher security and energy efficiency than the radio waves.
While the experimental system by the KAUST team achieved speeds of 2Gbit per second, most current Wi-Fi technologies only operate at speeds of a few tens of Mbits per second. Limited bandwidth has so far been a major obstacle preventing practical use of VLC; The main reason for this problem is the small bandwidth of the color converter—a component that converts blue LED light into the different colors needed to make the white light that is ultimately used to transmit data.
but the design of the color converter by the team overcomes this problem. While phosphors used in the system would only provide a limited bandwidth of maximum 12 megahertz, the additional use of perovskite greatly increases this value. As a result, the new color converter provides bandwidth that is 40 times greater than what is available through commercial converters. This bandwidth is also larger than that of non-phosphor-based color converters that scientists have recently been investigating, which have a bandwidth in the range of 40-200 MHz.
The team believes that white light generated by semiconductor lasers will one day replace the LED white light bulb for energy-efficient lighting. To achieve this objective, the researchers set the long-term goal to develop nanocrystals that can convert high-energy excitation photons from semiconductor lasers to Red-Yellow-Green-Blue (RYGB) lights at ultra-short photon lifetime.