Stable Photoelectrochemical Reactions at Solid/Solid Interfaces toward Solar Energy Conversion and Storage

Area of Science:

• Solid-state chemistry
• Electrochemistry
• Materials science

Background:

• Electrochemistry traditionally involves liquid electrolytes.
• Photoelectrochemistry at solid/solid interfaces is underexplored.
• Existing solid/liquid interfaces face stability challenges.

Purpose of the Study:

• To demonstrate stable photoelectrochemical reactions at a semiconductor/solid-electrolyte interface.
• To extend photoelectrochemistry to all-solid-state systems.
• To overcome limitations of solid/liquid interfaces.

Main Methods:

• Fabrication of an all-solid-state cell using Nb-doped anatase-TiO2 (a-TiO2:Nb) and Li3PO4 (LPO) solid electrolyte.
• Electrochemical measurements under light irradiation and in the dark.
• Analysis of current-potential characteristics.

Main Results:

• Achieved stable photoelectrochemical reactions at the a-TiO2:Nb/LPO solid-solid interface.
• Observed increased oxidative currents upon light irradiation above the flat-band potential.
• Demonstrated reversibility of photo-oxidation and dark reduction.

Conclusions:

• Successfully extended photoelectrochemistry to solid/solid interfaces in all-solid-state systems.
• The findings are driven by photoexcited electron migration and band bending.
• This advancement opens avenues for studying photoelectrochemical phenomena with improved stability and durability.