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Asymmetric Carbon-Film Hydrovoltaic Generators With Work-Function-Correlated Output in Liquid-Water and
Yulin Cai1, Dunren He2, Yaocheng Yang3
1Key Laboratory for Micro/Nano Optoelectronic Devices of Ministry of Education & Hunan Provincial Key Laboratory of Low-Dimensional Structural Physics and Devices, School of Physics and Electronics, Hunan University, Changsha, China.
Small Methods
|July 24, 2026
Summary
Researchers developed advanced carbon-film generators for hydrovoltaic energy harvesting. These devices offer improved output for self-powered electronics, using work-function engineering for enhanced performance in both liquid and moisture-based systems.
Area of Science:
- Materials Science
- Energy Harvesting
- Nanotechnology
Background:
- Hydrovoltaic energy harvesting shows potential for self-powered electronics.
- Current limitations include low output, scalability issues, and unclear mechanisms.
Purpose of the Study:
- To develop asymmetric carbon-film generators for efficient hydrovoltaic and moisture-electric energy harvesting.
- To explore the correlation between work function and output performance.
- To demonstrate scalable energy harvesting for practical applications.
Main Methods:
- Fabrication of asymmetric carbon-film hydrovoltaic generators (C-HEGs) and moisture-electric generators (C-MEGs).
- Performance characterization in liquid water and ambient humidity.
- Modular integration for scalable voltage and current output.
- Analysis using Ultraviolet Photoelectron Spectroscopy (UPS) and Kelvin Probe Force Microscopy (KPFM).
- Equivalent-circuit modeling to understand output mechanisms.
Main Results:
- Single C-HEG achieved ≈1.1 V and 450 µA cm⁻², C-MEG achieved ≈1.0 V and 350 µA cm⁻².
- Modular integration scaled voltage to ≈92 V with milliampere-level currents.
- Work-function contrast was identified as a key descriptor for electronic asymmetry and output voltage.
- Output is attributed to electronic asymmetry, water-mediated interfacial charging, and ion transport.
Conclusions:
- Asymmetric carbon-film generators offer a viable route for scalable hydrovoltaic and moisture-electric energy harvesting.
- Work-function engineering is crucial for optimizing generator performance.
- These generators hold promise for self-powered wearable electronics.
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