The binding and fluorescence quenching efficiency of nitroaromatic (explosive) vapors in fluorescent carbazole dendrimer thin films

Shaw, Paul E., Cavaye, Hamish, Chen, Simon S. Y., James, Michael, Gentle, Ian R. and Burn, Paul L. (2013) The binding and fluorescence quenching efficiency of nitroaromatic (explosive) vapors in fluorescent carbazole dendrimer thin films. Physical Chemistry Chemical Physics, 15 24: 9845-9853. doi:10.1039/c3cp51372f


Author Shaw, Paul E.
Cavaye, Hamish
Chen, Simon S. Y.
James, Michael
Gentle, Ian R.
Burn, Paul L.
Title The binding and fluorescence quenching efficiency of nitroaromatic (explosive) vapors in fluorescent carbazole dendrimer thin films
Journal name Physical Chemistry Chemical Physics   Check publisher's open access policy
ISSN 1463-9076
1463-9084
Publication date 2013-06-28
Year available 2013
Sub-type Article (original research)
DOI 10.1039/c3cp51372f
Open Access Status Not yet assessed
Volume 15
Issue 24
Start page 9845
End page 9853
Total pages 9
Place of publication Cambridge, United Kingdom
Publisher RSC Publications
Language eng
Subject 3100 Physics and Astronomy
1606 Physical and Theoretical Chemistry
Abstract We present a study on three generations of fluorescent carbazole dendrimers that exhibit strong binding with nitroaromatic compounds accompanied by photoluminescence (PL) quenching, making them attractive sensing materials for the detection of explosives such as 2,4,6-trinitrotoluene (TNT). The absorption and release of vapors of the (deuterated) TNT analogue 4-nitrotoluene (pNT) from thin films of the dendrimers were studied with a combination of time-correlated neutron reflectometry and PL spectroscopy. When saturated with pNT the PL of the films was fully quenched and could not be recovered with flowing nitrogen at room temperature but only upon heating to 40-80 degrees C. Although the majority of the absorbed pNT could be removed with this method the recovered films were found to still contain a residual pNT concentration of similar to 0.1 molecules per cubic nanometer. However, the proportion of the PL recovered increased with generation with the third generation dendrimer exhibiting close to full recovery despite the presence of residual pNT. This result is attributed to a combination of two effects. First, the dendrimer films present a range of binding sites for nitroaromatic molecules with the stronger binding sites surviving the thermal recovery process. Second, there is a large decrease of the exciton diffusion coefficient with dendrimer generation, preventing migration of the excitation to the remaining bound pNT.
Formatted abstract
We present a study on three generations of fluorescent carbazole dendrimers that exhibit strong binding with nitroaromatic compounds accompanied by photoluminescence (PL) quenching, making them attractive sensing materials for the detection of explosives such as 2,4,6-trinitrotoluene (TNT). The absorption and release of vapors of the (deuterated) TNT analogue 4-nitrotoluene (pNT) from thin films of the dendrimers were studied with a combination of time-correlated neutron reflectometry and PL spectroscopy. When saturated with pNT the PL of the films was fully quenched and could not be recovered with flowing nitrogen at room temperature but only upon heating to 40–80 °C. Although the majority of the absorbed pNT could be removed with this method the recovered films were found to still contain a residual pNT concentration of ~0.1 molecules per cubic nanometer. However, the proportion of the PL recovered increased with generation with the third generation dendrimer exhibiting close to full recovery despite the presence of residual pNT. This result is attributed to a combination of two effects. First, the dendrimer films present a range of binding sites for nitroaromatic molecules with the stronger binding sites surviving the thermal recovery process. Second, there is a large decrease of the exciton diffusion coefficient with dendrimer generation, preventing migration of the excitation to the remaining bound pNT.
Keyword Sensory materials
Polymer-films
Landmines
Q-Index Code C1
Q-Index Status Confirmed Code
Grant ID DP0986838
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Centre for Organic Photonics and Electronics
Official 2014 Collection
School of Chemistry and Molecular Biosciences
 
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