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Structural Engineering Three-Dimensional Nano-Heterojunction Networks for High-Performance Photochemical Sensing
Zain Ul Abideen1, Jun-Gyu Choi2, Jodie A Yuwono3
1Nanotechnology Research Laboratory, Research School of Chemistry, College of Science, Australian National University, Canberra, Australian Capital Territory 2601, Australia.
ACS Applied Materials & Interfaces
|November 21, 2023
Summary
Deep ultraviolet photoactivation enhances nanoscale heterojunction networks by tuning oxygen vacancies. This boosts photocatalytic activity for sensitive chemical detection in optoelectronic devices.
Area of Science:
- Materials Science
- Nanotechnology
- Photocatalysis
Background:
- Nanoscale heterojunction networks show promise for optoelectronic and photocatalytic applications.
- Surface defects in these networks hinder performance by causing charge trapping and recombination.
Purpose of the Study:
- To engineer photocatalytic properties of nanoscale heterojunction networks using deep ultraviolet (DUV) photoactivation.
- To investigate the role of oxygen vacancies in NiO-ZnO films for enhanced sensing capabilities.
Main Methods:
- Fabrication of thick (∼10 μm) NiO-ZnO films.
- In-depth X-ray photoelectron spectroscopy (XPS) analysis to characterize localized p-n nanoheterojunctions and oxygen vacancies (Vo).
- Density functional theory (DFT) calculations to understand analyte adsorption mechanisms.
Main Results:
- DUV photoactivation effectively tuned oxygen vacancies in NiO-ZnO nanoheterojunctions.
- Optimized oxygen vacancy concentration resulted in a 30-fold increase in photochemoresistive response.
- Detection of analytes at ppb levels was achieved at both 150 °C and room temperature.
- DFT calculations indicated an 80% increase in analyte adsorption energy.
Conclusions:
- DUV photoactivation is an effective strategy for controlling surface properties and enhancing photocatalytic activity in nanoscale heterojunction networks.
- Engineered NiO-ZnO networks demonstrate significant potential for applications in chemical sensors, photodetectors, and photoelectrochemical cells.
