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Title: Towards the Development of a Low-Cost Device for the Detection of Explosives Vapors by Fluorescence Quenching of Conjugated Polymers in Solid Matrices
Authors: Martelo, Liliana M. 
Neves, Tiago F. Pimentel das 
Figueiredo, João 
Marques, Lino 
Fedorov, Alexander
Charas, Ana 
Berberan-Santos, Mário N.
Burrows, Hugh D. 
Keywords: conjugated polymers; explosives detection; trace analysis; optical sensor; luminescence sensor
Issue Date: 3-Nov-2017
Publisher: MDPI
Project: TIRAMISU project. This project funded by the European Community’s Seventh Framework Program (FP7/2007-2013) under grant 284747 
Serial title, monograph or event: Sensors (Switzerland)
Volume: 17
Issue: 11
Abstract: Conjugated polymers (CPs) have proved to be promising chemosensory materials for detecting nitroaromatic explosives vapors, as they quickly convert a chemical interaction into an easily-measured high-sensitivity optical output. The nitroaromatic analytes are strongly electron-deficient, whereas the conjugated polymer sensing materials are electron-rich. As a result, the photoexcitation of the CP is followed by electron transfer to the nitroaromatic analyte, resulting in a quenching of the light-emission from the conjugated polymer. The best CP in our studies was found to be poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-bithiophene] (F8T2). It is photostable, has a good absorption between 400 and 450 nm, and a strong and structured fluorescence around 550 nm. Our studies indicate up to 96% quenching of light-emission, accompanied by a marked decrease in the fluorescence lifetime, upon exposure of the films of F8T2 in ethyl cellulose to nitrobenzene (NB) and 1,3-dinitrobenzene (DNB) vapors at room temperature. The effects of the polymeric matrix, plasticizer, and temperature have been studied, and the morphology of films determined by scanning electron microscopy (SEM) and confocal fluorescence microscopy. We have used ink jet printing to produce sensor films containing both sensor element and a fluorescence reference. In addition, a high dynamic range, intensity-based fluorometer, using a laser diode and a filtered photodiode was developed for use with this system.
ISSN: 1424-8220
DOI: 10.3390/s17112532
Rights: openAccess
Appears in Collections:I&D ISR - Artigos em Revistas Internacionais
FCTUC Química - Artigos em Revistas Internacionais

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