Li-Fi replaces Wi-Fi: data transmission at up to 224 Gbps using light

Researchers from the Korea Research Institute of Standards and Science have introduced a new platform for high-speed wireless data transmission based on Li-Fi technology.

Li-Fi (Light Fidelity) is a wireless communication method that uses the visible light spectrum (400–800 THz), similar to that emitted by LEDs. The proposed system achieves data transmission speeds of up to 224 Gbps — 100 times faster than traditional Wi-Fi.

Despite its high bandwidth and reduced interference, Li-Fi remains vulnerable in terms of security, as the signal can be intercepted by anyone within line of sight. To address this issue, a team led by Professor Himchan Cho from the Department of Materials Science and Engineering, in collaboration with Dr. Kyeong-In Lim from the Korea Research Institute of Standards and Science under the National Research Council of Science and Technology, developed a secure optical communication system with on-device data encryption for Li-Fi applications.

The system is based on highly efficient light-emitting triode devices using environmentally friendly quantum dots — low-toxicity, stable materials. Light is generated through an electric field concentrated in microscopic holes within a permeable electrode and emitted outward.

The device can simultaneously process two data input streams, converting them into light while also encrypting the information. Its external quantum efficiency — a measure of how effectively electrical energy is converted into light — reached 17.4%, close to the commercial benchmark of 20%. The device also achieved a brightness of 29,000 nits.

To better understand how the device converts information into light, the researchers conducted a transient electroluminescence analysis. They examined light emission behavior under brief, instantaneous voltage pulses. This analysis allowed them to study charge movement within the device over hundreds of nanoseconds and uncover the operational mechanism of dual-channel optical modulation within a single device.

The research findings were published in the journal "Advanced Materials".