Advances in optical sensing of explosive vapours

This project has received funding from the European Union’s Seventh Framework Programme for research, technological development and demonstration under agreement no 284747, and the EPSRC under EP/K503940/1, EP/K503162/1, and EP/N509759/1. IDWS acknowledges a Royal Society Wolfson Research Merit Award.Optical techniques for the detection of explosives are receiving increasing interest due to potentially fast responding, highly-sensitive systems. Conjugated polymers are suitable probe materials for this application since their fluorescence is quenched by electronegative materials including explosives. This can be used to make a sensor for explosive vapour, which can then give chemical information to help identify explosive devices, and complements other approaches such as metal detectors and ground penetrating radar. Whilst the principle has been known for some time, its practical implementation requires considerable development of instrumentation and materials, including preconcentration materials. This paper reports our current efforts to address these challenges, with particular emphasis on humanitarian demining and looking towards application in Improvised Explosive Device (IED) detection.Publisher PD

Sensing of explosive vapor by hybrid perovskites : effect of dimensionality

Funding: Engineering and Physical Sciences Research Council under grants EP/T01119X/1 and EP/K503940/1, and the NATO Science for Peace & Security programme under grant agreement MYP G5355.Lead halide perovskites are very promising materials for many optoelectronic devices. They are low cost, photostable, and strongly photoluminescent materials, but so far have been little studied for sensing. In this article, we explore hybrid perovskites as sensors for explosive vapor. We tune the dimensionality of perovskite films in order to modify their exciton binding energy and film morphology and explore the effect on sensing response. We find that tuning from the 3D to the 0D regime increases the PL quenching response of perovskite films to the vapor of dinitrotoluene (DNT)—a molecule commonly found in landmines. We find that films of 0D perovskite nanocrystals work as sensitive and stable sensors, with strong PL responses to DNT molecules at concentrations in the parts per billion range. The PL quenching response can easily be reversed, making the sensors reusable. We compare the response to several explosive vapors and find that the response is strongest for DNT. These results show that hybrid perovskites have great potential for vapor sensing applications.Publisher PDFPeer reviewe

Explosive vapour sensing with organic and hybrid semiconductors

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Improved organic semiconductor explosive sensors for application on minefields

Here we present progress made in the development of an organic semiconductor based sensor system for explosive vapours. The sensors, originally developed in the TIRAMISU project, monitor a change in fluorescence from a polymer film when it is exposed to trace vapours of TNT and similar explosives. The approach could be promising for applications in remote explosive scent trace (REST detection) for the technical survey of mine fields. Successful deployment of the detection system in the field, however, requires an improved method for sample collection and delivery to the sensor, and an approach to address the potential problem of false detectionof distractants. We report here recent progress addressing these challenges