Blanco, Elias 1 ; Martinez, Jose, I 2 ; Maria Parra-Alfambra, Ana 1 ; Dolores Petit-Dominguez, Maria 1 ; del Pozo, Maria 1 ; Martin-Gago, Jose A 2 ; Casero, Elena 1 ; Quintana, Carmen 1 1 Univ Autonoma Madrid, Dept Quim Analit & Anal Instrumental, Fac Ciencias, Francisco Tomas Y Valiente 7,Campus Excelencia, E-28049 Madrid, Spain, Spain email@example.com 2 CSIC, Inst Mat Sci Madrid ICMM, Mat Sci Factory, Sor Juana Ines de la Cruz 3, Madrid 28049, Spain, Spain
Many molecules quench their fluorescence upon adsorption on surfaces. Herein we show that the interaction of thiabendazole, a widespread used fungicide of the benzimidazole family, with nanosheets of transition metal dichalcogenides, particularly of WS2, leads to a significant increase, more than a factor of 5, of the fluorescence yield. This surprising effect is rationalized by DFT calculations and found to be related to the inhibition of the intramolecular rotation between the benzimidazole and thiazole groups due to a bonding rigidization upon interaction with the MoS2 surface. This non-covalent adsorption leads to a redistribution of the molecular LUMO that blocks the non-radiative energy dissipation channel. This unusual behaviour does not operate either for other molecules of the same benzimidazole family or for other 2D materials (graphene or graphene oxide). Moreover, we found that a linear dependence of the emission with the concentration of thiabendazole in solution, which combined with the specificity of the process, allows the development of a highly sensitive and selective method towards thiabendazole determination that can be applied to real river water samples. An excellent detection limit of 2.7 nM, comparable to the best performing reported methods, is obtained with very good accuracy (E-r <= 6.1%) and reproducibility (RSD <= 4.1%) in the concentration range assayed.
PHYSICS CONDENSED MATTER;MATERIALS SCIENCE MULTIDISCIPLINARY;ROOM-TEMPERATURE PHOSPHORESCENCE;AGGREGATION-INDUCED EMISSION;CAPILLARY-ELECTROPHORESIS;BENZIMIDAZOLE FUNGICIDES;GRAPHENE OXIDE;WATER SAMPLES;MOS2;QUANTIFICATION;IDENTIFICATION;CARBENDAZIM;Physical; Chemical and Earth Sciences