Improved hydrogen evolution with SnS₂ quantum dot-incorporated black Si photocathode

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Black silicon (bSi) is a promising photocathode material due to its light-trapping and surface area properties.
• Insufficient dynamics for the hydrogen evolution reaction (HER) limit the performance of black silicon.
• Quantum dots offer unique properties for enhancing electrochemical reactions.

Purpose of the Study:

• To develop a novel photoelectrode by incorporating tin sulfide quantum dots (SnS₂ QDs) into black silicon (bSi).
• To improve the photoelectrochemical hydrogen evolution (PEC-HER) activity and stability of black silicon.
• To investigate the effect of SnS₂ QDs on carrier dynamics and band bending at the bSi/electrolyte interface.

Main Methods:

• Fabrication of a photoelectrode using ultrasmall tin sulfide quantum dots (SnS₂ QDs) incorporated into black silicon (bSi).
• Characterization of the material's structure and properties.
• Electrochemical measurements to evaluate photoelectrochemical hydrogen evolution (PEC-HER) performance, including onset potential and photocurrent.

Main Results:

• The SnS₂/bSi photoelectrode exhibited enhanced PEC-HER activity with a positive onset potential of 0.235 V vs. RHE.
• A high photocurrent of 1.23 mA cm⁻² at 0 V vs. RHE was achieved.
• The SnS₂ QDs improved band bending, suppressed carrier recombination, and led to long-term stability, with saturated photocurrents up to ~41 mA cm⁻².

Conclusions:

• The integration of SnS₂ QDs significantly boosts the PEC-HER performance of black silicon by enhancing carrier dynamics.
• The developed SnS₂/bSi photoelectrode shows great potential for efficient and stable hydrogen production.
• This work offers a promising strategy for designing advanced photocathode materials for renewable energy applications.