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

这项NIRT提案的重点是为紧急救援人员和第一响应者开发一种新型碳纳米管电离化学传感器，使“现场”监测成为可能。该传感器重量轻，结构紧凑，坚固耐用，价格合理，功耗低（电池供电），可以在实时模式下提供快速响应的污染物的明确识别。智力优势：我们的传感想法利用纳米管尖端附近产生的极高电场，作为在低电压下诱导气体电离和电击穿的一种手段。通过监测击穿电压，可以识别气体（每种气体都有特征击穿行为），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群（电极阵列）进行一系列实验，以获得对纳米管电极附近气体和混合物的电离和分解的基本机制的基本理解。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预测的支持。基于从这项研究中获得的理解，我们将组装集成设备来检测混合物中的痕量分析物，我们将量化灵敏度，选择性和传感器功耗。更广泛的影响：现场化学传感对环境监测、化学过程控制、空间任务、农业和医疗应用至关重要。鉴于国土安全问题，传感的广泛影响也得到了充分认识。为整合教学与研究，我们将在课程中引入感测实验与多媒体虚拟实验室。我们还将与NSEC中心联系，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.