posted on 2024-01-04, 22:05authored byJiayun Feng, Jiayue Wen, Shang Wang, He Zhang, Jingxuan Ma, Xuanyi Hu, Zhuohuan Wu, Geng Li, Zhiyuan Wang, Min Jia, Yanhong Tian
This study reports a concept of a planar hygroelectric
generator
fabricated by nanosized graphene oxide (GO) flakes. On the surface
of the GO film, flexible reduced GO (rGO) electrodes were fabricated
by nanosecond laser irradiation, and a gradient of oxygen content
between the anode and the cathode was established by electric polarization
in a high-humidity environment. This device generates an open-circuit
voltage of up to 0.6 V when the unit is placed in contact with moisture
and has a good repeatability. Besides, material characterization methods
such as Raman spectrum and X-ray photoelectron spectroscopy analyses
have confirmed that the laser-irradiated GO area and the GO near the
cathode have a lower oxygen content, and the hydroxyl groups (−OH)
are mostly removed among all kinds of oxygen-containing functional
groups. Therefore, a possible ion absorption theory was raised to
explain the electricity generation mechanism in the nanoscale, in
which the absorption of proton and the migration of OH– ions cause the charge transfer. In addition, this planar hydroelectric
generator was successfully integrated with a resistive strain sensor
to construct a fully flexible self-powered sensing system. The output
voltage signal is controlled by both the environmental humidity and
the strain change, providing a strategy to expand the application
field of this hygroelectric generator to various sensing areas.