López Torres, DiegoElosúa Aguado, CésarPappas, Georgios A.Konstantaki, MariaKlini, ArgyroLappas, AlexandrosArregui San Martín, Francisco JavierPissadakis, Stavros2024-01-152024-01-152023Lopez-Torres, D., Elosua Aguado, C., Pappas, G. A., Konstantaki, M., Klini, A., Lappas, A., Arregui, F. J., Pissadakis, S. (2023) Piezotronic, ZnO overlaid bragg grating organic vapor sensors. IEEE Sensors Journal, 23(12), 12536-12543. https://doi.org/10.1109/JSEN.2023.3270966.1530-437X10.1109/JSEN.2023.3270966https://academica-e.unavarra.es/handle/2454/47049We present a zinc oxide (ZnO) out-cladding, overlaid optical fiber Bragg grating sensor, for the detection of vapors of common alcohols and acetone at concentrations lower than 25 ppm while operating at room temperature (RT). The optical fiber sensing results indicate a chemostriction effect occurring in the ZnO layer when exposed to volatile organic compounds (VOCs), which in turn induces shifts in the cladding, and most importantly, in the core confined, Bragg mode. The sensor exhibits a maximum sensitivity of ∼1 pm/ppm to ethanol vapors, with exposure to other alcohol vapors (isopropanol and methanol) showing lower sensitivities; also, response to acetone vapors was traced at ∼0.5 pm/ppm. X-ray diffraction (XRD) measurements of the ZnO nanolayer revealed that, in saturated ethanol vapors atmosphere, the polycrystalline ZnO film undergoes a contraction by 0.6% of the interplanar distance corresponding to the (002) crystalline direction, denoting the chemostrictive effect through an underlying piezotronic mechanism. XRD measurements and optical fiber sensing data are further correlated by numerical simulations carried out, so to study the strain interactions of the ZnO layer with the silica glass optical fiber.application/pdfeng© 2023 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other work.PiezotronicsTilted optical fiber Bragg grating (TOFBG) sensorsVolatile organic compounds (VOCs)Zinc oxide (ZnO)info:eu-repo/semantics/article2024-01-15info:eu-repo/semantics/openAccess