Inkjet printed LED based pH chemical sensor for gas sensing.

Area of Science:

• Chemical sensors
• Optical detection
• Inkjet printing technology

Background:

• Predictable sensor behavior is crucial for wireless sensor networks (WSN).
• Optical chemical sensors offer sensitive detection methods.
• Gaseous acetic acid detection is important in various industrial applications.

Purpose of the Study:

• To fabricate and evaluate an inkjet-printed optical chemical sensor for gaseous acetic acid.
• To assess the sensor's performance, including sensitivity, accuracy, and signal-to-noise ratio.
• To compare the reproducibility of inkjet printing versus drop casting for sensor fabrication.

Main Methods:

• Fabrication of a colorimetric chemical sensor using inkjet printing.
• The sensor formulation included bromophenol blue, tetrahexylammonium bromide, and ethyl cellulose in 1-butanol.
• Detection was performed using a paired emitter-detector diode (PEDD) optical detector.
• Characterization involved layer thickness, response/recovery times, and reproducibility studies.

Main Results:

• The inkjet-printed sensor demonstrated good sensitivity, low power consumption, accuracy, and high signal-to-noise ratios.
• Inkjet printing resulted in significantly improved reproducibility (5.5% RSD) compared to drop casting (68.0% RSD).
• Sensor stability was confirmed through intra-day and inter-day studies.

Conclusions:

• Inkjet printing is a viable and highly reproducible method for fabricating optical chemical sensors.
• The developed sensor is suitable for accurate and sensitive gaseous acetic acid detection in WSN applications.
• This approach offers a cost-effective and reliable sensing solution.