from the conferences organized by TANGER Ltd.
Single-crystalline silicon with a porous structure at the micrometer to nanometer level is currently used as a sensor for electrochemical or optical-based detection because of its exceptional optical, surface, and electronic properties. However, further research into this structured nanomaterial is ongoing and points to its potential use in other detection and sensor fields. This work focuses on the preparation and application of porous silicon sensor substrates for the dual-mode detection of perfluorooctanoic acid (PFOA). PFOA is captivating because it is a known contaminant and a substance that the human body cannot naturally excrete, which over time leads to the accumulation of this compound in the blood and organs and can cause health complications. In the first step of the realization of this work, a number of samples with different morphologies and sizes of the porous structure were prepared and the best ones were subsequently used. Then, the porous Si (pSi) surface was coated with a thin layer of gold by a vacuum sputtering method to increase the surface conductivity and introduce plasmon-active properties. The sample surface was modified with amino-containing organic moieties to ensure high surface affinity towards PFOA molecules (and their selective capture). The successful modification of the surface morphology, chemistry, and properties was verified by scanning electron microscopy (SEM) and UV-Vis. PFOA detection was subsequently performed in two modes, using electrochemical impedance spectroscopy (EIS) and surface-enhanced Raman spectroscopy (SERS) approaches. The EIS and SERS experiments showed that the sensor is reliable for determination of the PFOA in water at a significant concentration. In conclusion, the successful experiments in the detection of PFOA give us hope that the developed sensor could be used for the detection of other hazardous substances with similar size, structure, and functional groups.
Keywords: Porous silicon, nanomaterial, sensor technologies, PFOA, EIS, SERS, environmental detection, health implications© This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.