Enhanced optical oxygen sensing property based on Pt(II) complex and metal-coated silica nanoparticles embedded in sol–gel matrix

Abstract

This paper presents a metal enhanced optical oxygen sensor that comprises an optical fiber coated at one end with platinum (II) meso-tetrakis(pentafluorophenyl)porphyrin (PtTFPP) and silver metal-coated nanoparticles embedded in an n-octyltriethoxysilane (Octyl-triEOS)/tetraethylorthosilane (TEOS) composite xerogel. The sensitivity of the optical oxygen sensor is quantified in terms of the ratio IN2/IO2, where IN2 and IO2 represent the detected fluorescence intensities in pure nitrogen and pure oxygen environments, respectively. The experimental results show that the oxygen sensor has a sensitivity of 167. The response time was 2.6s when switching from pure nitrogen to pure oxygen, and 36s when switching in the reverse direction. The experimental results show that compared to oxygen sensor based on Pt(II) complex immobilized in the sol–gel matrix, the proposed optical fiber oxygen sensor has higher sensitivity. In addition to the increased surface area per unit mass of the sensing surface, the metal-coated silica nanoparticles also increase the sensitivity because the metal-enhanced fluorescence. The proposed optical sensor has the advantages of low cost and high sensitivity for oxygen monitoring using a cheap LED as a light source.