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Quasicrystal Nanosheet/α-Fe2O3 Heterostructure-Based Low Power NO2 Sensors: Experimental and DFT Studies
Sumit Kumar1, Mirabbos Hojamberdiev2, Anyesha Chakraborty3
1Department of Electrical Engineering, Indian Institute of Technology Jodhpur, Jodhpur 342030, India.
ACS Applied Materials & Interfaces
|March 22, 2024
Summary
Highly sensitive and selective nitrogen dioxide (NO2) gas sensors were developed using two-dimensional quasicrystal (2D QC) nanosheets and alpha-iron oxide (α-Fe2O3) nanoparticles. These novel sensors offer enhanced performance for industrial and medical applications.
Area of Science:
- Materials Science
- Nanotechnology
- Chemical Sensing
Background:
- High-performance, low-power sensors are crucial for industrial emissions monitoring, environmental sensing, and medical diagnostics.
- Two-dimensional quasicrystal (2D QC) nanosheets, specifically metallic multicomponent Al70Co10Fe5Ni10Cu5, show potential for gas sensing due to their catalytic and electronic properties.
Purpose of the Study:
- To develop highly sensitive and selective nitrogen dioxide (NO2) gas sensors.
- To utilize low-cost and scalable fabrication techniques involving 2D QC nanosheets and α-Fe2O3 nanoparticles.
- To investigate the sensing mechanism and performance enhancement through nanoheterojunction formation.
Main Methods:
- Fabrication of gas sensors using 2D QC nanosheets and α-Fe2O3 nanoparticles.
- Characterization of sensor performance, including sensitivity and selectivity towards NO2.
- Analysis of sensor conduction type and resistance changes upon gas exposure.
- Density Functional Theory (DFT) calculations to examine adsorption energy and charge transfer at heterojunction interfaces.
Main Results:
- The optimal 2D QC nanosheet-loaded α-Fe2O3 sensor exhibited a sensitivity of 32% for 1 ppm NO2 at 150 °C, 3.5 times higher than bare α-Fe2O3 sensors.
- Sensors demonstrated p-type conduction with reduced resistance upon exposure to NO2, indicating effective gas detection.
- Nanoheterojunctions formed between 2D QC and α-Fe2O3 significantly improved charge transport and sensing signal.
- Excellent NO2 selectivity was observed over other oxidizing and reducing gases, supported by DFT calculations.
Conclusions:
- The integration of 2D QC nanosheets with α-Fe2O3 nanoparticles creates highly sensitive and selective NO2 gas sensors.
- Nanoheterojunction formation is key to enhanced sensing performance, improving charge transport and signal amplification.
- The developed sensors show promise for practical applications in environmental monitoring and industrial safety due to their performance and fabrication scalability.
