NIRT: Miniaturized Chemical Sensors Featuring Electrical Breakdown near Carbon Nanotube Tips

这项NIRT计划的重点是开发一种新型的碳纳米管电离化学传感器，用于紧急救援人员和急救人员，这将使“现场”监测成为可能。该传感器重量轻、结构紧凑、坚固耐用、价格实惠、耗电量低(电池供电)，并能以实时模式和快速响应提供明确的污染物识别。智能优点：我们的传感想法利用纳米管尖端附近产生的极高电场作为一种手段，在低电压下诱导气体电离和电击穿。通过监测击穿电压，可以识别气体(每种气体都有特征的击穿行为)，通过监测放电电流，可以确定气体浓度。在这个项目中，我们将对单个纳米管以及管束(电极阵列)进行一系列实验，以基本了解纳米管电极附近气体物种和混合物的电离和击穿的基本机制。这些实验将得到密度泛函理论对尖锐纳米管尖端附近气体电离的预测的支持。在这项研究的基础上，我们将组装集成设备来检测混合物中的痕量分析物，并对灵敏度、选择性和传感器功耗进行量化。更广泛的影响：现场化学传感对于环境监测、控制化学过程、空间飞行任务、农业和医疗应用至关重要。鉴于国土安全问题，感知的更广泛影响也得到了很好的认识。为了使教学和科研相结合，我们将在课程中引入传感实验和多媒体虚拟实验室。我们还将联系国家安全委员会中心的外展活动，向K-12学生和教师介绍纳米技术。

This NIRT proposal focuses on developing a novel carbon nanotube ionization chemical sensor for emergency rescue crews and first responders that will enable "on-site" monitoring. The proposed sensor is light-weight, compact, robust, affordable, consumes low power (battery operated) and can provide definitive identification of contaminants in real-time mode with fast response.Intellectual Merit: Our idea for sensing takes advantage of the extremely high electric fields that are generated near nanotube tips as a means of inducing ionization and electrical breakdown of the gas at low voltages. By monitoring the breakdown voltage, the gas can be identified (every gas has a characteristic breakdown behavior) and by monitoring the discharge current, the gas concentration can be determined. In this project we will perform a series of experiments with individual nanotubes as well as ensembles of tubes (electrode arrays) to gain a fundamental understanding of the basic mechanisms for ionization and breakdown of gas species and mixtures near nanotube electrodes. The experiments will be supported by density functional theory predictions for gas ionization near sharp nanotube tips. Based on the understanding gained from this study we will assemble integrated devices to detect trace amounts of analytes in mixtures and we will quantify the sensitivity, selectivity and sensor power consumption. Broader Impact: On-site chemical sensing is critical to environmental monitoring, control of chemical processes, space missions, agricultural and medical applications. Broader impact of sensing is also well recognized in light of homeland security issues. To integrate teaching and research we will introduce sensing experiments and multimedia virtual-labs into the curriculum. We will also connect to the outreach of the NSEC Center to introduce Nanotechnology to K-12 students and teachers.