2004 Progress Report: Low Cost Organic Gas Sensors on Plastic for Distributed Environmental MonitoringEPA Grant Number: R830899
Title: Low Cost Organic Gas Sensors on Plastic for Distributed Environmental Monitoring
Investigators: Subramanian, Vivek
Institution: University of California - Berkeley
EPA Project Officer: Carleton, James N
Project Period: May 1, 2003 through April 30, 2006
Project Period Covered by this Report: May 1, 2004 through April 30, 2005
Project Amount: $328,000
RFA: Environmental Futures Research in Nanoscale Science Engineering and Technology (2002) RFA Text | Recipients Lists
Research Category: Nanotechnology , Safer Chemicals
The objective of this research project is to develop low-cost sensors for environmental monitoring.
This project focused on the development of low-cost arrayed organic sensors for environmental monitoring applications. The project has been underway for 2 years. In Year 1 of the project, we successfully developed a baseline sensor technology and used it to detect numerous common organic environmental contaminants, including various alcohols, ketones, and other solvents often found in industrial waste. In this past year, we made substantial progress in improving the robustness, reliability, and repeatability of the technology and increased the level of integration within the baseline sensor process.
The sensors used in this project are solution-processed, backgated, organic, semiconductor-based thin film transistors. These devices serve as excellent sensors for two reasons. First, because of the backgated structure, the channel material is exposed directly to the environment, thus providing an easily accessed probe area. Second, as has been established in previous years, the sensitivity of these organic semiconductor materials to environmental species is generally high, making their use in sensors advantageous. We have demonstrated organic sensors using several different organic semiconductors, including several polythiophenes and pentacene derivatives. These have been used to achieve sensing of several organic environmental contaminants. Studies also have been performed on the cycle-life of these sensors, and quantitative models for sensor operation have been identified. In the past year, these studies have led to the development of a differential sensing technique that eliminates the drift and degradation issues that were identified as problems in the previous year. Therefore, at this point, the sensor technology’s robustness and reliability has been improved substantially over that reported in Year 1 of the project.
Additionally, further integration of the sensor technology has been achieved, with fully integrated arrays having been demonstrated along with associated differential sensing circuitry necessary for drift correction. Thus, at the end of Year 2 of the project, we have realized successfully a fairly robust and repeatable sensor technology, and we are continuing our characterization and improvement of the same through a focused program aimed at improving both materials and devices as well as the requisite circuit and usage techniques.
This year, we have met our intended goals of demonstrated arrayed operation of the sensors and have successfully developed techniques for mitigating drift and reliability issues in the same. In the next year, we will continue further integration of the correction methodology into the printed array, and we will focus on deployment of the sensors in testing of environmental contaminants.
Journal Articles on this Report : 1 Displayed | Download in RIS Format
|Other project views:||All 6 publications||1 publications in selected types||All 1 journal articles|
||Liao F, Chen C, Subramanian V. Organic TFTs as gas sensors for electronic nose applications. Sensors and Actuators B 2005;107(2):849-855.||