Electrical Nerve Agents Sensors Based on Chemically Functionalized Nanomaterials A. Carella * , S. Clavaguera * , C. Celle * , S. Lenfant ** , D. Vuillaume ** , E. Dubois ** , V. Passi ** , L. Gorintin *** , P. Bondavalli *** and J.-P. Simonato * * CEA Grenoble / LITEN / DTNM 17 rue des Martyrs, 38054 Grenoble Cedex 9, France E-mail: jean-pierre.simonato@cea.fr ** IEMN – CNRS, BP 60069 Avenue Poincaré, 59652 Villeneuve d'Ascq Cedex, France *** Thales Research & Technology 1, avenue Augustin Fresnel, 91767 Palaiseau, France ABSTRACT A chemical receptor specific to traces of organophosphorus agents (OPs) has been synthesized and grafted to carbon nanotube or silicon nanoribbon based electrical devices. Our results show that it is possible to detect efficiently traces of OPs with good selectivity notably with the use of silicon nanoribbons by monitoring the Drain-Source current of the SiNR-FET at an optimum back Gate voltage as a function of time. Keywords: nerve agents • sensors • carbon nanotubes • silicon nanoribbons • nanotechnology 1 INTRODUCTION The threat of a chemical attack on homeland and military forces continues to grow and recent examples such as Iraqi gas attacks or Tokyo terrorist act have clearly demonstrate that organophosphorous agents are powerful neurotoxic molecules that can actually be used as chemical warfare agents and weapons of chemical terrorism. [1] Due to the structural diversity of toxic chemicals, there is no single ideal sensor for all potential chemical agents, and many sensors with widely different sensitivities are needed for operational processes. Presently, the methods used to detect organophosphorus nerve agents are mostly inadequate for today’s expending requirements. New sensors are highly expected, with improved performances such as low weight, very limited false positive, low power consumption, high sensibility, high selectivity, etc. The ease of production and extreme toxicity of OP nerve agents underscores the need to detect these odorless and colorless chemicals. Today, there is an important need for wandering applications of selective sensors for organophosphorus (OP) based toxic gases for instance for individual soldier protection. In the same context we have to take into account the urgent need of passive and low consumption multipoint sensors with extremely low rate false alarm for preventing toxic gas attacks that could be installed in public areas such as subway stations, stadiums, malls... O P O F O P O F O P O F O O P O Cl O O P O Cl O Sarin Soman DFP DCP DPCP Scheme 1. Chemical structures of some OPs In this communication we will present new sensing techniques developed for the detection of organophosphorus nerve agents based on the recent developments of nanosciences and nanotechnologies. The miniaturized detectors devices based on electrical detection, i.e. resistors or transistors, using semiconducting parts made either of functionalized carbon nanotubes or silicon nanowires. 2 CARBON NANOTUBE BASED SENSORS The first kind of sensors we realized where made of single walled carbon nanotubes (SWCNTs) in a resistor configuration. First, the SWCNTs where dispersed in NMP (N-methylpyrrolidone) by ultrasonication for 30 minutes. Centrifugation at 13 000 g afforded a grey solution of SWCNTs suitable for spray coating technique. The substrates are made of gold electrodes, obtained by standard lithography on silicon dioxide. The density of the network of SWCNTs was controlled by spray duration and controlled by SEM analysis. NSTI-Nanotech 2012, www.nsti.org, ISBN 978-1-4665-6275-2 Vol. 2, 2012 130