Mesoporous nanostructures-based fiber optic pH sensors: Synthesis, structure-tailoring, physiochemical and sensing stimuli. (August 2021)

• Record Type: Journal Article
• Authors: Alshoaibi, Adil; Islam, Shumaila
• Is Part Of: Materials research bulletin. Volume 140(2021)
• Publication Date: 2021-08
• Subjects: Silica-titania nanoparticles -- Sol-gel -- pH sensor -- Organic dyes -- Porosity; Materials -- Periodicals; Crystal growth -- Periodicals; Matériaux -- Périodiques; Cristaux -- Croissance -- Périodiques; Crystal growth; Materials; Periodicals; 620.11
• DOI: 10.1016/j.materresbull.2021.111332
• Languages: English
• ISSNs: 0025-5408

Abstract

Graphical abstract: Highlights: SiO2, TiO2, and SiO2 -TiO2 are synthesized and encapsulated by a mixture of four organic dyes by sol-gel method at (60 °C–80 °C). Crack-free morphology, surface roughness, and thermal stability is attributed to the effect of dyes immobilization on the host matrices. The sensitivity ∼ 16.34 a.u./pH for d -SNPs, 133.06 a.u./pH for d -TNPs, and 45.14 a.u./pH for d -STNPs matrix is reported. The fast time response is estimated as 0.35 s, 0.33 s, and 0.31 s in pH 12 for d -SNPs, d -TNPs, and d -STNPs matrices, respectively. Abstract: Owing to opto-chemical sensing, three matrices i.e., SiO2, TiO2, and SiO2 -TiO2 are synthesized and a mixture of four different organic dyes encapsulated in them through the sol-gel method. Thermally stable, large surface area 434 m 2 /gm, 197 m 2 /gm, 332 m 2 /g, and refractive index 1.49, 1.8, 1.5 at 632 nm are observed for d -SNPs (dyes encapsulated silica nanoparticles), d -TNPs (dyes encapsulated titania nanoparticles), and d -STNPs (dyes encapsulated silica-titania nanoparticles), respectively. When the evanescent field interacts with the fiber optic coating, absorption varied due to pH change and the output intensity is recorded as a sensor response in terms of transmission. The prepared sensors exhibited linear response, non-leachability, and stability towards high pH 12. The fast time response is estimated ∼ 0.35 s, 0.33 s, and 0.31 s in pH 12 for d -SNPs, d -TNPs, and d -STNPs, respectively. Therefore, these prepared optical fiber sensing devices have the potential for practical pH sensing applications.