Preparation of Bi‐Doped ZnO Thin Film over Optical Fiber and Their Application as Detection of Ethylenediamine in an Aqueous Medium Based on the Evanescent Field Technique

Abstract

Synthesis of pure ZnO and bismuth-doped ZnO (xBi/Zn) (x ¼ 6 wt%) thin-film based optical fiber sensor and their material/optical characterization such as Brunauer-Emmett-Teller (BET) analysis, field-emission scanning electron microscopy (FESEM), and energy dispersive X-ray (EDX) analysis is reported. As-prepared material such as xBi/Zn is deposited over the optical fiber, and optimum clad thickness in the range of 2-5 μm is achieved through MATLAB simulation to enhance the feasible evanescent field interaction with gas analyte molecules. The modal field analysis of the sensing probe before and after the deposition of xBi/Zn is also studied using COMSOL Multiphysics Modeling software and find strong light propagation into the LP 04 mode. The sensing probes are tested in different chemicals and ethylenediamine (EDA) is found to be the most suitable candidate in the concentration range of 100-800 ppm. The response time of the ZnO and xBi/Zn-doped thin-film-based optical sensor is found to be 20 and 15 s, whereas the corresponding sensitivity (%) is 1.078 and 3.483, respectively. The repeatability test of the sensor is also carried out which reveals good response stability.

Structural, Morphological, and Optical Properties of Ag‐Doped TiO2 Thin‐Film over Fiber Optic Substrate for Sensing Applications

“…[ 13 ] Prior to building a fiber optic sensing head, the extent of etching of the cladding layer to achieve maximum evanescent field propagation was optimized using MATLAB simulation and reported in detail in our previous article. [ 14 ] Initially, a small length (≈2 cm) of the fiber clad was modified through etching by dilute HF. Subsequently, the seed layer of the ethanolic solution of titanium isopropoxide was prepared over the fiber surface with the help of the dip‐coating method.…”

“…If the EDA analytes interact with O ab , it generates N 2 gas with CO 2 molecules that have a pungent smell. [ 14 ] However, it emits extra electrons which cause variation in charge density, RI, and conductivity of the material. Several amine analytes were measured but EDA was found to have robust behavior due to the multidentate chelate effect.…”

Fast fabrication, gas sense characteristics and kinetics of cubic Ti-BIPA-TC-MOF film composite optical waveguides

“…In the N 1s spectrum (figure 2(b)), two peaks at E B = 400.1 and 401.5 eV indicate the presence of imide (-NH-C=O) and pyrrole nitrogen [25]. Two spin orbit peaks at E B = 458.6 and 464.5 eV in the Ti 2p spectrum (figure 2(c)) corresponded to Ti 2p 1/2 and 2p 3/2 , indicating a +4 valence state for Ti in the Ti 2 -(TpA) 2 -H 2 BIPA, whose can be linked with organic ligands to form a stable cubic MOF [26]. The O 1s spectrum (figure 2(d)) also showed three matching peaks at E B = 529.9, 531.6 and 532.9 eV, attributed to the metal oxygen, C=O and O-C=O binding forms of oxygen, respectively [27].…”

Conductometric Gas Sensor Based on MoO3 Nanoribbon Modified with rGO Nanosheets for Ethylenediamine Detection at Room Temperature

“…Simultaneously, an electron depletion layer formed on the MoO 3 surface, causing a decrease in the charge carrier density of the composite and increasing sensor resistance [29]. When the sensor was exposed to reduced EDA vapor, the EDA molecules adsorbed onto the material's surface and interacted with the adsorbed oxygen species (Equation ( 9)) [55]. Meanwhile, the electrons were released from the reaction and back into the material, thereby inducing a decrease in the thickness of the depletion layer and reducing the resistance of the composites [43].…”