Band engineering for efficient catalyst-substrate coupling for photoelectrochemical water splitting

Area of Science:

• Materials Science
• Photovoltaics
• Electrochemistry

Background:

• Efficient solar water splitting devices require optimized photo-converters and catalysts, alongside effective coupling.
• Voltage losses at interfaces can significantly hinder overall device performance.

Purpose of the Study:

• To investigate the origin of voltage loss at the interface between a thin-film amorphous silicon tandem cell and a TiO2 corrosion protection layer.
• To understand the role of interfacial layers in solar water splitting device efficiency.

Main Methods:

• Utilized X-ray Photoelectron Spectroscopy (XPS) to analyze the interface.
• Conducted a series of model experiments on individual device components.
• Disassembled the complete device to analyze its constituents separately.

Main Results:

• Identified the formation of a silicon dioxide (SiO2) interfacial layer between the TiO2 protection layer and the silicon cell.
• Confirmed that this SiO2 layer is the primary cause of the observed voltage loss.

Conclusions:

• The formation of an interfacial SiO2 layer is directly responsible for the voltage loss in the studied solar water splitting device.
• Understanding and mitigating this interfacial layer is key to enhancing solar water splitting efficiency.