Orthogonal gas sensor arrays by chemoresistive material design

Area of Science:

• Materials Science
• Chemical Sensing
• Sensor Array Technology

Background:

• Gas sensor arrays struggle with analyte discrimination and robustness due to sensor cross-selectivity.
• Weakly-selective sensors limit the performance of conventional gas sensor arrays.
• Achieving high accuracy and precision in complex gas mixtures remains a challenge.

Purpose of the Study:

• To investigate the impact of sensor orthogonality on gas sensor array accuracy and precision.
• To explore how systematic alterations in array size and composition affect performance.
• To demonstrate the benefits of selective sensor design for improved gas mixture analysis.

Main Methods:

• Formation of sensor arrays with varying numbers (2-5) of selective and non-selective sensors.
• Systematic variation of array composition to achieve different degrees of sensor orthogonality.
• Performance evaluation using 60 random combinations of ammonia, acetone, and ethanol at ppb to low ppm concentrations.

Main Results:

• An array with highly orthogonal sensors (Si:MoO3, Si:WO3, Si:SnO2) achieved excellent prediction coefficients of determination (R2): 0.96 for ammonia, 0.99 for acetone, and 0.88 for ethanol.
• Arrays with collinear sensors (e.g., Pd:SnO2, Pt:SnO2, Si:SnO2) showed limited improvement in gas predictions.
• In some cases, collinear sensor arrays performed worse than individual selective sensors, highlighting the importance of orthogonality.

Conclusions:

• High orthogonality in sensor arrays, achieved through the use of distinctly selective sensors, significantly enhances gas mixture analysis accuracy and precision.
• Selective sensor design is crucial for improving the discrimination power and stability of gas sensor arrays.
• Orthogonal sensor arrays offer a promising approach to overcome the limitations of conventional gas sensors in real-world applications.