Silica Nanoparticles Coated with Smaller Au Nanoparticles for the Enhancement of Optical Oxygen Sensing

Abstract

In the vicinity of metal nanostructures, phosphorescent intensity can be greatly enhanced through the localized surface plasmon resonance (LSPR). The enhancement of phosphorescence intensity in noble-metal nanoparticle (NP) systems is highly dependent on the overlap of the absorbance peak of a noble metal with that of phosphorescent dyes. When the peak of the NPs' absorption spectra has a maximum overlap with that of these dyes, the phosphorescence enhancement is the largest. Here, we use a seeded growth method to synthesize SiO 2 / Au NPs with tunable plasmonic resonance and compare their phosphorescence enhancement for an oxygen range of 0−21%. The measurement sensitivity of oxygen is strongly dependent on the enhancement of phosphorescence. When used with PtTFPP, when the absorbance peak of the SiO 2 /Au NPs has a maximum overlap with that of PtTFPP, the phosphorescence enhancement factor is as high as 7; the sensitivity of oxygen concentration is as high as 75. Moreover, we also optimize the performance by varying the number of NPs to eliminate the nonradiative energy-transfer (NRET) process and self-quenching.

On the Use of Polymer-Based Composites for the Creation of Optical Sensors: A Review

“…The works of recent years presented in this review show a trend towards the use of various fillers forming composites, which, on the one hand, make it possible to increase the fluorescent response, and hence the measurement accuracy, and, on the other hand, to lower the detection limit [ 108 , 233 ].…”

“…Yin et al showed an example of such a synergistic effect in improving the performance of an optical molecular oxygen sensor [ 108 ]. The authors took as a basis a composite sensor consisting of mesoporous silica gel particles with an adsorbed dye PtTFPP, which are distributed in a polymer matrix [ 170 , 171 ].…”

Steady-state and fluorescence lifetime quenching of self-assembled diphenylalanine/coumarin nanostructures as a method to determine dissolved O2in water

“…However, actual sensors are not often proposed because it is difficult to achieve sensitivity and selectivity high enough to ensure reliable measurements. Immobilization of organic dyes on support matrices permeable only to oxygen, or combination with other materials are frequently reported strategies in order to achieve an effective sensor [6][7][8][9][10]. O 2 optical sensors based on transition metal complexes, are alternatives due to their long phosphorescence lifetime, a requirement for efficient energy transfer from the sensing unit to molecular oxygen through collisional quenching, yielding high sensitivity to the sensor [11,12].…”