Advanced Optimization of Optical Carbon Dioxide Sensor Through Sensitivity Enhancement in Anodic Aluminum Oxide
Manna Septriani Simanjuntak1, Rispandi2, Cheng-Shane Chu1,3,4
1International Ph.D. Program in Innovative Technology of Biomedical Engineering and Medical Devices, Ming Chi University of Technology, New Taipei City 243303, Taiwan.
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The current research developed an optical carbon dioxide (CO2) sensor using anodized aluminum oxide (AAO) as the substrate. We developed an optical carbon dioxide (CO2) sensor utilizing CdSe/ZnS quantum dots (QDs) as the fluorescent dye and Phenol Red as the pH indicator. The QDs acted as the CO2-responsive fluorophore and were embedded in a polyimide butyl methacrylate (polyIBM) matrix. This sensing solution was applied to an anodized aluminum oxide (AAO) substrate, which provided a porous and stable platform for sensor fabrication. Photoluminescence measurements were conducted using the coated AAO substrate, with excitation from a 405 nm LED light source. The sensor exhibited red fluorescence emission at 570 nm and could detect CO2 concentrations in the linear range of 0-100%. Experimental results showed that fluorescence intensity increased with CO2 concentration, achieving a sensitivity of 211. A wavelength shift of 0.1657 nm/% was observed, indicating strong interactions among CO2 molecules, Phenol Red, and the QDs within the AAO matrix. The sensor demonstrated a response time of 55 s and a recovery time of 120 s. These results confirm the effectiveness of this optical sensing approach in minimizing fluctuations from the excitation light source and highlight the potential of the AAO-supported QDs and Phenol Red composite as a reliable CO2 sensing material. This advancement holds promise for applications in both medical and industrial fields.
