EXP-SA: Ultra Sensitive Organic Transistor Based Explosives Detector

Stanford University, Stanford CA

Investigators

Abstract

TITLE: EXP-SA: Ultra Sensitive Organic Transistor Based Explosives Detector Stanford University Zhenan Bao 0730710 Intellectual Merit: Organic monolayer transistors are attractive for ultra-sensitive detection of explosive chemical vapors. By using a mono-molecular layer as the active organic semiconductor layer, the effect of exposure to explosive chemicals is readily sensed and can lead to a much more dramatic change in the current flow than when a thicker organic semiconductor layer is used. Currently, such transistors are being fabricated using expensive electron beam lithography because only small ordered domain sizes are formed from self assembled monolayers. This research seeks to understand the materials requirements and design rules for organic semiconductors needed for explosive chemical sensing applications. The project pursues several methods to efficiently and reliably fabricate large arrays of monolayer transistors, including a new method for forming large ordered monolayers by simple spin-coating, Langmuir Blodgett film approach, and direct writing of electrodes onto vacuum evaporated organic semiconductor monolayers using Dip Pen Nanolithography. The project then investigates the sensing capability of such films. The project also designs and synthesizes new organic semiconductors or binding sites that can improve the sensitivity and selectivity of the monolayer transistor sensors for the detection of strongly oxidizing or reducing explosive chemicals. Broader Impact: The research has the potential to significantly improve the understanding of organic semiconductor materials for explosive chemical detection. A new class of materials with high performance and robust properties is being designed, synthesized, and characterized using monolayer transistor sensor as a test bed. Graduate and undergraduate students involved in the project will be equipped with a combination of technical engineering skills, basic scientific understanding, and communication skills to prepare them to contribute to the forefront of sensor technology.