Fluorescent dendrimers for the detection of explosives

Paul Shaw

The detection of explosives, particularly with compact portable sensors, remains an ongoing security and technological challenge. The quenching of the fluorescence of organic semiconductors by explosives such as TNT is one promising solution. In this talk I will provide an overview of the principles behind fluorescence quenching before introducing a series of compounds for sensing that vary in terms of size, shape and the number of chromophores. As such, these compounds provide an ideal platform for understanding the processes that govern the quenching of the fluorescence in both solution and thin films. By performing simultaneous measurements of the neutron reflectivity and fluorescence intensity of thin films we can monitor the diffusion and concentration of vapours of a TNT-analogue within the film and obtain quantitative measurements of the quenching efficiency. These experiments provide insights into not just the sensing process but also the photophysical and electronic properties of the sensing materials.