Highly Efficient Moisture-Triggered Nanogenerator Based on Graphene Quantum Dots

A high-performance moisture triggered nanogenerator is fabricated by using graphene quantum dots (GQDs) as the active material. GQDs are prepared by direct oxidation and etching of natural graphite powder, which have small sizes of 2–5 nm and abundant oxygen-containing functional groups. After the treatment by electrochemical polarization, the GQDs-based moisture triggered nanogenerator can deliver a high voltage up to 0.27 V under 70% relative humidity variation, and a power density of 1.86 mW cm–2 with an optimized load resistor. The latter value is much higher than the moisture-electric power generators reported previously. The GQD moisture triggered nanogenerator is promising for self-power electronics and miniature sensors.