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Atomically Altered Hematite for Highly Efficient Perovskite Tandem Water-Splitting Devices.
Gurudayal1, Rohit Abraham John1, Pablo P Boix2
1School of Materials Science and Engineering, Nanyang Technological University, Nanyang Avenue, Singapore, 639798, Singapore.
Chemsuschem
|April 4, 2017
Summary
Hematite photoanodes were enhanced using hydrothermal growth and atomic layer deposition, significantly boosting solar-to-hydrogen efficiency for water splitting. This breakthrough sets a new benchmark for hematite-based tandem systems in renewable energy storage.
Area of Science:
- Materials Science
- Renewable Energy
- Electrochemistry
Background:
- Photoelectrochemical (PEC) cells offer a promising route for solar energy storage via water splitting.
- Hematite (α-Fe2O3) is a cost-effective and stable photoanode material, but suffers from poor charge transport and kinetics, limiting solar-to-hydrogen (STH) efficiency.
Purpose of the Study:
- To enhance the efficiency of hematite photoanodes for water photolysis.
- To achieve high photocurrents and STH conversion efficiency using a novel fabrication method.
Main Methods:
- Solution-based hydrothermal growth of hematite.
- Post-growth surface modification using atomic layer deposition (ALD).
- Fabrication of a tandem system with a perovskite solar cell for unassisted water splitting.
Main Results:
- Modified hematite photoanodes exhibited a photocurrent of 3.12 mA/cm² at 1.23 V vs RHE, a >5-fold increase compared to unmodified Fe2O3.
- A plateau photocurrent of 4.5 mA/cm² was achieved at 1.5 V vs RHE.
- The tandem system demonstrated an STH conversion efficiency of 3.4% for unassisted water splitting.
Conclusions:
- The combined hydrothermal growth and ALD approach significantly enhances hematite photoanode performance.
- The developed tandem system represents a new benchmark for hematite-based photoelectrochemical water splitting.
- This work paves the way for more efficient solar fuel production.