Designing Atomic Interface in Sb₂S₃/CdS Heterojunction for Efficient Solar Water Splitting

Area of Science:

• Materials Science
• Renewable Energy
• Photocatalysis

Background:

• Antimony trisulfide (Sb2S3)-based devices are promising for solar energy conversion.
• Cadmium sulfide (CdS) buffer layers improve charge separation but suffer from cation diffusion at the Sb2S3 interface, creating defects.
• Stable interfaces are crucial for efficient Sb2S3 solar energy devices.

Purpose of the Study:

• To investigate the impact of an ultrathin aluminum oxide (Al2O3) interlayer on the Sb2S3/CdS heterojunction.
• To suppress interfacial defects caused by cation diffusion.
• To enhance the performance of Sb2S3-based solar energy conversion devices.

Main Methods:

• Fabrication of Ag:Sb2S3/Al2O3/CdS heterojunctions.
• Characterization of interfacial properties and defect suppression.
• Evaluation of water-splitting photocathode performance in neutral electrolyte.

Main Results:

• The Al2O3 interlayer effectively prevented Cd2+ cation diffusion into the Sb2S3 layer.
• Defect formation at the Sb2S3/CdS interface was significantly suppressed.
• The Ag:Sb2S3/Al2O3/CdS photocathode achieved a 2.78% solar-to-hydrogen efficiency, compared to 1.66% for the control device.

Conclusions:

• Ultrathin Al2O3 interlayers are effective in stabilizing Sb2S3/CdS heterojunctions.
• Interface engineering is critical for optimizing Sb2S3-based solar energy devices.
• This approach provides a pathway for developing high-performance stibnite-type semiconductor solar energy converters.