Share Email Print
cover

Proceedings Paper

Quantum dot material for the detection of explosive-related chemicals
Author(s): Vincent P. Schnee; Marc D. Woodka; Daniel Pinkham
Format Member Price Non-Member Price
PDF $14.40 $18.00
cover GOOD NEWS! Your organization subscribes to the SPIE Digital Library. You may be able to download this paper for free. Check Access

Paper Abstract

Changes in the fluorescence of semiconductor nanocrystals were explored as a potential sensing mechanism for the detection of chemicals associated with landmines, IEDs and HME materials. A series of quantum dots (QDs) with fluorescence emissions spanning the visible spectrum was investigated using the Stern-Volmer relationship, specifically measuring the effect of quencher concentration on QD fluorescence intensity and photo-excited lifetime. The series of QDs was investigated with respect to their ability to donate excited-state electrons to an electronwithdrawing explosive related compound (ERC). Electron transfer was monitored by observing the steady-state fluorescence signal and the excited-state lifetimes of the QDs in the presence of ERC1. Increased sensitivities of QDs towards ERC1 were observed as the size and emission wavelength of the QDs decreased. As the QDs size decreased, the Stern-Volmer quenching constants increased. The larger QD exhibited the lowest Ksv and is thought to be quenched by a purely static quenching mechanism. As QD size decreased, an additional collisional quenching mechanism was introduced, denoted by a non-linearity in the quenching-vs-concentration Stern-Volmer plot. Increases in quenching efficiency were due to increased excited-state lifetimes, and the introduction of a collisional quenching mechanism. The quenching constant for the smallest QD was approximately an order of magnitude higher than those of similarly evaluated commercially available fluorescent polymers, suggesting that QDs could be exploited to develop sensitive detectors for electron-withdrawing compounds such as nitroaromatics.

Paper Details

Date Published: 10 May 2012
PDF: 7 pages
Proc. SPIE 8357, Detection and Sensing of Mines, Explosive Objects, and Obscured Targets XVII, 83571J (10 May 2012); doi: 10.1117/12.921403
Show Author Affiliations
Vincent P. Schnee, U.S. Army Night Vision & Electronic Sensors Directorate (United States)
Marc D. Woodka, U.S. Army Night Vision & Electronic Sensors Directorate (United States)
Daniel Pinkham, U.S. Army Night Vision & Electronic Sensors Directorate (United States)


Published in SPIE Proceedings Vol. 8357:
Detection and Sensing of Mines, Explosive Objects, and Obscured Targets XVII
J. Thomas Broach; John H. Holloway, Editor(s)

© SPIE. Terms of Use
Back to Top