A Multi-channel System for Qualitative Explosive and Drug Detection

It is well known that under blue LED/laser illumination a class of synthetic conjugated polymers can create fluorescence, and after absorbing a certain class of explosive vapors the fluorescence will be quenched thus the explosives can be detected. The unsolved problems are how can we detect drug, TATP and nitro aromatic explosives with the same device, how can we distinguish different explosives and drugs, and how can we avoid false alarms; solving these problems are crucial for world security. We have developed a new synthetic conjugated polymer with single molecule layer and coated on porous silicon with large surface area to increase quenching signal at least one order, based on this new film a small handheld explosive detector with sensitivities of 0.1 pg for TNT and 0.1 ng for black gun powder are obtained. Many explosives and drugs (such as TNT, RDX, PETN, black gun powder, cocaine, etc.) have been tested, from their quenching curves and our data base we are able to distinguish them qualitatively and avoid false alarms. Therefore we believe our detector can be used not only for battle field but also for airports, government entrances and other security check points. Last year, after face to face competition, our device was selected as the only security detector for the G20 summit held in Hangzhou, China. Here, we will give our detailed designs to let readers develop detectors by themselves to counter terrorism in the world and save lives.