title: Unambiguous detection of nitrated explosive vapours by fluorescence quenching of dendrimer films.
abstract: Unambiguous and selective standoff (non-contact) infield detection of nitro-containing explosives and taggants is an important goal but difficult to achieve with standard analytical techniques. Oxidative fluorescence quenching is emerging as a high sensitivity method for detecting such materials but is prone to false positives—everyday items such as perfumes elicit similar responses. Here we report thin films of light-emitting dendrimers that detect vapours of explosives and taggants selectively—fluorescence quenching is not observed for a range of common interferents. Using a combination of neutron reflectometry, quartz crystal microbalance and photophysical measurements we show that the origin of the selectivity is primarily electronic and not the diffusion kinetics of the analyte or its distribution in the film. The results are a major advance in the development of sensing materials for the standoff detection of nitro-based explosive vapours, and deliver significant insights into the physical processes that govern the sensing efficacy.
authors.affiliation: Centre for Organic Photonics &Electronics, The University of Queensland, Queensland 4072, Australia.
authors.forename: Yan
authors.initials: Y
authors.lastname: Geng
authors.affiliation: Centre for Organic Photonics &Electronics, The University of Queensland, Queensland 4072, Australia.
authors.forename: Mohammad A
authors.initials: MA
authors.lastname: Ali
authors.affiliation: Centre for Organic Photonics &Electronics, The University of Queensland, Queensland 4072, Australia.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Clulow
authors.affiliation: Centre for Organic Photonics &Electronics, The University of Queensland, Queensland 4072, Australia.
authors.forename: Shengqiang
authors.initials: S
authors.lastname: Fan
authors.affiliation: Centre for Organic Photonics &Electronics, The University of Queensland, Queensland 4072, Australia.
authors.forename: Paul L
authors.initials: PL
authors.lastname: Burn
authors.affiliation: Centre for Organic Photonics &Electronics, The University of Queensland, Queensland 4072, Australia.
authors.forename: Ian R
authors.initials: IR
authors.lastname: Gentle
authors.affiliation: Centre for Organic Photonics &Electronics, The University of Queensland, Queensland 4072, Australia.
authors.forename: Paul
authors.initials: P
authors.lastname: Meredith
authors.affiliation: Centre for Organic Photonics &Electronics, The University of Queensland, Queensland 4072, Australia.
authors.forename: Paul E
authors.initials: PE
authors.lastname: Shaw