Optical sensing of triethylamine using CdSe aerogels

Abstract

The photoluminescence (PL) response of highly porous CdSe aerogels to triethylamine (TEA) is investigated and compared to results from prior studies on single crystals and nanoparticle-polymer composites. As-prepared CdSe aerogels show significant and reversible enhancement of luminescence intensity upon exposure to TEA relative to the intensity in pure argon carrier gas. The enhancement in the PL response is dependent on the concentration and linear over the range of TEA concentration studied (4.7 x 10(3)-75 x 10(3) ppm). The sensing response of previously tested samples exhibits saturation behavior that is modeled using Langmuir adsorption isotherms, yielding adsorption equilibrium constants in the range 300-380 atm( - 1). The response is sensitively affected by the surface characteristics of the aerogel; when the wet gels are treated with pyridine prior to aerogel formation, the response to TEA is diminished, and when as-prepared aerogels are heated in a vacuum, no subsequent response is observed. Deactivation is attributed to an increase in surface oxide (SeO(2)) and decrease in surface Cd(2 + ) Lewis acid sites. Sensing runs of approximately one hour have little impact on the morphology or crystallinity of the aerogels, but do result in partial removal of residual thiolate ligands left over from the gelation process.

Mixed Aerogels from Au and CdTe Nanoparticles

“…Since the recent discovery of such porous structures built solely from colloidal semiconductor nanocrystals (NCs) like CdS,28 progress in this field includes the fabrication of strongly emitting CdSe and CdSe/ZnS NC based aerogels with their emission spectrum resembling that of the nanocrystals themselves and hence being tunable with the NC size owing to the quantum confinement effect 29–31. Such CdSe aerogels were already applied as selective optical sensors 32. By using PbS nanoparticles for example, the optical activity of the resulting aerogels may additionally be adapted to the near infrared spectral region 28.…”

Enzyme‐Encapsulating Quantum Dot Hydrogels and Xerogels as Biosensors: Multifunctional Platforms for Both Biocatalysis and Fluorescent Probing

“…However, most reported enzyme-encapsulating materials used in the biosensing field are silica-gel-based and aerogel-based materials that are manufactured through the sol-gel process by addition of biomolecules into the silica precursors. [8] Up to now, only a few reports on QD-gel-based sensors are published, [9] although QDs have been widely utilized as a fluorescence (FL) probe in bioanalysis. [10] The formation of 3D networked QD aerogels through the sol-gel method is mainly based on the partial removal of thiolate ligands by oxidants or the photochemical treatment.…”

Versatile Aerogels for Sensors

“…There are some other detection methods for the biosensors besides the electrochemical detection, such as fluorescent detection, surface‐enhanced Raman scattering detection (SERS), and electrochemiluminescent detection . For the aerogel‐based fluorescent detection, the general strategy is introduction of fluorescent materials in the 3D network of aerogels to get fluorescent aerogels.…”