Domestic researchers have presented a new platform for Li-Fi that can simultaneously enhance transmission speed and security, surpassing the limits of existing optical communication devices. Li-Fi is a wireless communication technology that utilizes visible light in the visible spectrum, such as light from light-emitting diodes (LEDs), offering speeds up to 100 times faster than existing Wi-Fi.
A research team led by Professor Cho Him-chan at the Korea Advanced Institute of Science and Technology (KAIST) collaborated with researcher Lim Kyung-geun from the Korea Research Institute of Standards and Science (KRISS) to develop a technology for 'on-device encryption optical communication devices' using Li-Fi, the team noted on the 24th. The research was published in the international journal Advanced Materials on the 30th of last month and was also selected as a cover paper.
Professor Cho's research team created a high-efficiency light-emitting triode device using low-toxicity, sustainable ultra-fine semiconductor particles (quantum dots). The device developed by the team generates light using an electric field. In particular, the electric field concentrates in a very small hole (pinhole) area present in the transparent electrode and passes through beyond the electrode, allowing this device to process two input data simultaneously.
Using this principle, the research team developed a technology called 'on-device encryption optical transmission devices.' The key to this technology is that it converts information into light while simultaneously encrypting it on the device itself. This means that data transmission with enhanced security is possible even without complex separate equipment.
Using this principle, the research team developed a technology called 'on-device encryption optical transmission devices.' The key to this technology is that it converts information into light while simultaneously encrypting it on the device itself. This means that enhanced security data transmission is possible even without complex separate equipment.
The external quantum efficiency (EQE) is an indicator of how efficiently electricity is converted into light, with the standard for commercialization generally being around 20%. The device developed this time recorded an EQE of 17.4%, and the luminance also exceeded the maximum brightness of a smartphone OLED screen at 2,9000 nits, achieving more than 10 times higher brightness.
Additionally, the research team analyzed the light emission characteristics of the device when a voltage was applied momentarily for a very short time to gain a more accurate understanding of how the device converts information into light. Through this, they identified the operating mechanism implemented within a single device by analyzing the movement of charges within the device in the order of several hundred picoseconds (nanoseconds).
Professor Cho Him-chan said, 'This research has presented a new communication platform that can enhance security capabilities while increasing transmission speed, surpassing the limits of existing optical communication devices.' He added, 'This technology, which enables encryption and transmission to be realized simultaneously without additional equipment, could be widely applied in various fields where security is important in the future.'
References
Advanced Materials(2025), DOI: https://doi.org/10.1002/adma.202503189