Inspired by the Surface of Rice Leaves

- Develops a high-efficiency triboelectric nanogenerator using the surface characteristics of rice leaves and the microstructure of a nonflammable elastomer -

- Can be used as an artificial leaf that generates electricity from water and wind, and as a wearable wristband that produces electricity from human movement -

- Published in the world-renowned journal Advanced Functional Materials by Wiley (IF: 18.5, top 3.7% in the field)

Professor Gi-Won Lee (Department of Chemical Engineering), in collaboration with Professor Gil-Won Cho of POSTECH and Professor Seung-Goo Lee of Ulsan University, successfully developed a wearable triboelectric nanogenerator inspired by the surface of rice leaves. This research was published as a Front Cover paper in an internationally renowned journal in the field of materials science.

Professor Gi-Won Lee from the Department of Chemical Engineering

The paper, titled ‘Anisotropic Fluorinated-Elastomer-Blended Micro-Dominoes for Wearable Triboelectric Nanogenerator,’ was published on August 8, 2024, in the SCI international journal Advanced Functional Materials (JCR top 3.7% in materials engineering, IF 18.5).

Triboelectric nanogenerators (TENGs), which convert mechanical energy into electrical energy by using a charging phenomenon generated when two different objects come into contact, have been the focus of active research in recent years. The small and flexible TENG is gaining attention as a next-generation portable power source in fields such as electronic skin, the Internet of Things (IoT), healthcare, and environmental monitoring. However, to apply these nanogenerators in everyday life, various issues such as energy conversion efficiency, stretchability and deformability, operational stability, and ease of manufacturing must be addressed.

Recently, to address these challenges, a research team led by Professor Gi-Won Lee from Kwangwoon University’s Department of Chemical Engineering, Professor Gil-Won Cho from POSTECH’s Department of Chemical Engineering, and Professor Seung-Goo Lee from Ulsan University’s Department of Nanoenergy Chemistry developed a high-efficiency triboelectric nanogenerator using a micro-domino structure made of fluorinated elastomers.

Inspired by dominoes that fall sequentially with a small force, the research team applied the micro-domino structure to the device, and found that the micro-dominoes easily deformed on the surface of the contact object and make broad contact, generating friction electricity with a high efficiency of 1,290 V output voltage and 9.8 W/m² power density when a person moves (frequency 5 Hz).

Furthermore, the team used fluorinated elastomers as the material for the nanogenerator, which not only generates electrical energy through contact with water, but also stays clean at all times, making it last longer.

In particular, like water droplets on the surface of a leaf, water droplets dropped on the domino structure of the nanogenerator roll easily in one direction, so it was possible to harvest electricity from a single droplet and achieve high energy conversion efficiency.

Based on these device properties, the team showed that the device could be utilized as an artificial leaf that effectively generates electricity from wind or raindrops, and demonstrated a wearable nanogenerator band that can generate electricity with the touch of a wrist, shaking, or washing hands.

Professor Gi-Won Lee stated, "The nanogenerator developed in this study can generate electricity with high efficiency from water and wind, making it a potential alternative to solar cells in regions with frequent rain and wind. It is also expected to be used as a portable power source for many future wearable devices, eliminating the need for charging."

The findings were recently published as a Front Cover article in the world-renowned journal Advanced Functional Materials, and the research was supported by the following projects.

Https://doi.org/10.1002/adfm.202470177

- National Research Foundation of Korea: Ministry of Science and ICT, Ministry of Education

- Kwangwoon University Internal Research Project

Figure 1. Schematic and application examples of wearable nanogenerators with micro-domino structures