Schottky-functionalized Z-scheme heterojunction: Improved photoelectric conversion efficiency and immunosensing

Area of Science:

• Materials Science
• Nanotechnology
• Biomedical Engineering

Background:

• Photoelectrochemical (PEC) biosensors require efficient photovoltaic materials for high sensitivity.
• Developing advanced materials is crucial for improving biosensor performance in disease diagnosis.

Purpose of the Study:

• To design a Schottky-functionalized direct Z-scheme heterojunction photovoltaic material.
• To fabricate a highly sensitive PEC biosensor for carcinoembryonic antigen (CEA) detection.

Main Methods:

• Electrodeposition of gold nanoparticles on bismuth oxyhalide composites (depAu/BiOI/BiOBr).
• Formation of a direct Z-scheme heterojunction and gold Schottky junction.
• Development of a 'signal-off' PEC immunoassay using sandwich immunotechnology.

Main Results:

• The novel material exhibited enhanced light harvesting and photoelectric conversion efficiency.
• The PEC immunoassay demonstrated a wide detection range (1.0 fg/mL-2.0 ng/mL) for CEA.
• Achieved a low detection limit of 0.11 fg/mL with excellent selectivity and stability.

Conclusions:

• The developed Schottky-functionalized Z-scheme heterojunction material significantly boosts PEC biosensor sensitivity.
• This PEC immunoassay platform offers a promising approach for early disease diagnosis and tumor marker analysis.