Optofluidic laser explosive sensor with ultralow detection limit and large dynamic range using donor-acceptor-donor organic dye

Due to the significance of explosive detection for homeland security and environmental protection, the research of new materials and new methodologies for sensing electron-deficient explosive nitryl aromatics is urgently imperative. In this paper we demonstrate an optofluidic laser sensor for explosive detection by using a highly electron-rich dye (dye-1) with donor-acceptor-donor conjugated structure. The design and facile synthesis process of dye-1 are described. Theoretical calculations, UV–vis absorption and fluorescence spectra are investigated to understand the structure-property relations. Exceptionally high quantum yield of emission in solution is achieved. As a proof of concept, electron-deficient explosive molecule 2, 4-dinitrotoluene (DNT) is used as a model analyte to evaluate the performance of the optofluidic laser sensor. Experimental results indicate that the optofluidic dye laser sensor achieves a large dynamic range with 4 orders of magnitude and an ultralow limit of detection (10 nM), much better than fluorescent sensor. This work provides a route to expand the applications of optofluidic laser for sensitive biochemical detection through specific luminescent materials.