Luminescent, Freestanding Composite Films of Au₁₅ for Specific Metal Ion Sensing

Abstract

A highly luminescent freestanding film composed of the quantum cluster, Au(15), was prepared. We studied the utility of the material for specific metal ion detection. The sensitivity of the red emission of the cluster in the composite to Cu(2+) has been used to make a freestanding metal ion sensor, similar to pH paper. The luminescence of the film was stable when exposed to several other metal ions such as Hg(2+), As(3+), and As(5+). The composite film exhibited visual sensitivity to Cu(2+) up to 1 ppm, which is below the permissible limit (1.3 ppm) in drinking water set by the U.S. environmental protection agency (EPA). The specificity of the film for Cu(2+) sensing may be due to the reduction of Cu(2+) to Cu(1+)/Cu(0) by the glutathione ligand or the Au(15) core. Extended stability of the luminescence of the film makes it useful for practical applications.

Luminescent films for chemo- and biosensing

“…3). 21,23,99 For instance, Zhang et al developed a facile method of immobilizing BSA-Au NCs into polyelectrolytes to obtain the Au NC-containing film for the detection of Cu 2+ . The visual detection limit of Ag + was determined to be 25 ppm and even to be lower (5 ppm) for Hg 2+ and Pb 2+ .…”

“…99 The glutathione (GSH)-stabilized Au NCs were incorporated into the film via the combination of the amino group from chitosan with the carboxyl group from GSH. 99 The glutathione (GSH)-stabilized Au NCs were incorporated into the film via the combination of the amino group from chitosan with the carboxyl group from GSH.…”

An overview of luminescent bio‐based composites

“…George et al demonstrated the feasibility of using gold nanoclusters in a device arrangement using chitosan as the film matrix (Figure ). The Au 15 quantum nanoclusters were encapsulated in a cyclodextrin, aiming to increase both chemical and thermal stability of the clusters, before being dispersed on a dried chitosan film soaked with sodium citrate to enhance the film strength.…”

“…(Adapted from Ref. , with permission from American Chemical Society). [Color figure can be viewed in the online issue, which is available at http://wileyonlinelibrary.com.…”

Tailored Nanoparticles for Clean Technology–Achieving Size and Shape Control

“…Particle size and shape have played crucial roles in optimizing the performance of commercial applications, such as air purification systems, new generations of automobile exhaust catalysts, nanoelectronics, photothermal cancer therapy, and various sensors [279][280][281][282][283][284][285]. The surface plasmon resonance phenomenon plays a crucial role in many sensors reported in the literature, as it allows tuning of the sensor properties via both particle size and shape [240,279,286,287].…”