AQM has developed a method of detecting high-energy compounds using non-toxic, photoluminescent silicon quantum dots. We have demonstrated the detection of a series of nitroaromatic compounds such as mononitrotoluene (MNT), nitrobenzene (NB), dinitrotoluene (DNT), trinitrotoluene (TNT), as well as, nitramine RDX and nitrate ester PETN by exploiting the optical response of functionalized silicon nanocrystals on treated paper or cotton. The treated substrate remains unchanged and the coating is invisible to the eye.

This simple paper or cloth-based system shows instant detection of nitro-based compounds in solution, vapor and solid phases by luminescence quenching at nanogram detection levels. Using paper or cotton swab substrates as sensing motifs is a simple, cost effective approach to achieve real-time detection through visualization under a handheld UV lamp. The degree of photoluminescent quenching is proportional to the concentration of explosive (i.e., the higher the concentration, the more efficient the quenching and the darker the image on the paper sensor).