Luminescent CdSe Quantum Dot Arrays for Rapid Sensing of Explosive Taggants

Chemical sensors based on fluorescent quantum dots have attracted intense interest because of their excellent optical and electronic properties compared to the routinely employed fluorescent organic dyes. This study reports a CdSe QD-polymer-based luminescent chemosensor, which is based on an array containing either green-emitting or red-emitting CdSe QDs embedded in polycaprolactone as a polymer host matrix. We evaluate the sensing capability of the nanocomposites by exposing both sensors to vapors of explosive taggants, explosive-like molecules, and some common solvents. Both nanocomposites exhibit a very fast response time of <30 s. The limit of detection of the sensors for 3-nitrotoluene, 4-nitrotoluene 2,3-dimethyl-2,3-dinitrobutane, and picric acid was found to be 0.055, 2.7, 0.7 and 916.4 ng, respectively. The sensor array constitutes a powerful tool to discriminate between explosive taggants (3-nitrotoluene, 4-nitrotoluene, and 2,3-dimethyl-2,3-dinitrobutane) and shows specific molecular recognition toward picric acid. This type of miniaturized luminescent QD-based nanocomposites might form the basis of a sensing platform technology to perform effective chemical detection and identification of explosive taggants preblast and postblast.