CAREER: Real-Time, Selective Gas Sensing in Complex Gas Compositions by Molecular Sieving via Robust Two-Dimensional Heterostructures

该奖项的全部或部分资金来自《2021年美国救援计划法案》(公法117-2)。在不断变化的世界中，人们对实时、区分、敏感和低成本的气体传感器的需求越来越大，以促进人类的健康和安全。它们是非侵入性医疗筛查和诊断、环境传感和爆炸物检测所必需的。然而，复杂的气体成分，如在人类呼吸或环境中发现的那些，使传统的选择性气体检测具有挑战性。目前的固态传感器虽然成本低且坚固耐用，但在复杂气体成分中的选择性较差。这项NSF职业研究计划旨在研究层状二维材料之间的层间间隙的气体筛选能力，以用于可调、选择性的气体分子电检测。该项目的教育和推广目标是通过基于课程的本科研究经验、实习和当地高中的指导，在STEM项目中吸引未被充分代表的少数族裔。该职业提案的研究目标是通过研究和开发2D层状过渡金属氧化物(TMO)组成的异质结构的碳化硅上2D外延石墨烯(EG)无与伦比的电子和传感特性，解决低成本固态气体传感器中的速度和选择性问题。TMO与生俱来的化学选择性和独特的宽层间间距可以通过离子操作来实现可调的分子筛。此外，通过排除动力学直径大于有效层间距的分子，可以实现复杂气体成分中的选择性气体传感。该程序主要有五个任务：(1)研究范德华外延在EG上大规模电沉积TMOS；(2)通过结构、电学和化学表征，表征和量化合成的异质结构的主要气敏机理；(3)以密度泛函理论、数值计算和材料表征为指导，通过设计和制作电导/阻抗气体传感器，评估具有不同插层离子的2D异质结构的气敏性能；(4)通过改变分子尺寸、温度、压力和湿度来测试传感器对不同气体成分和条件的性能；以及(5)开发一种基于传感器输出度量的预测算法，以减少与类似大小和阻抗响应的分子可能的交叉敏感性，并集成到能够基于呼吸和环境感知的便携式传感平台中。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

This award is funded in whole or in part under the American Rescue Plan Act of 2021 (Public Law 117-2).There has been an increasing need for real-time, discriminate, sensitive, and low-cost gas sensors to promote human health and safety in a changing world. These are needed for non-invasive medical screening and diagnostics, environmental sensing, and explosives detection. However, complex gas compositions, like those found in the human breath or the environment, make conventional selective gas detection challenging. Current solid-state sensors, while low-cost and robust, suffer from poor selectivity in complex gas compositions. This NSF CAREER research program aims to investigate the gas sieving capabilities of the interlayer gap between layered two-dimensional materials for the tunable, selective, electrical detection of gas molecules. This project's educational and outreach goal is to engage underrepresented minorities in STEM programs through course-based undergraduate research experiences, internships, and mentorships with local high schools.The research objective of this CAREER proposal is to address the speed and selectivity problems in low-cost solid-state gas sensors by investigating and exploiting the unparalleled electronic and sensing properties of 2D epitaxial graphene (EG) on silicon carbide with heterostructures comprised of 2D layered transition metal oxides (TMO). TMOs innate chemical selectivity and uniquely wide interlayer spacings can be manipulated ionically to enable tunable molecular sieves. Furthermore, selective gas sensing within complex gas compositions can be achieved by rejecting molecules with kinetic diameters larger than the effective interlayer spacing. The program has main five tasks: (1) Investigate the large-scale electrodeposition of TMOs on EG by van der Waals epitaxy; (2) characterize and quantify the dominant sensing mechanisms of the synthesized heterostructures through structural, electrical, and chemical characterization; (3) assess the gas sensing performance of the 2D heterostructures with various intercalated ions through the design and fabrication of conductometric/impedimetric gas sensors, guided by density functional theory, numerical calculations, and material characterization; (4) test the sensor performance against different gas compositions and conditions by varying molecule size, temperature, pressure, and humidity; and (5) develop a predictive algorithm based on sensor output metrics to reduce possible cross-sensitivity with molecules of similar size and impedance response and integrated into a portable sensing platform capable of breath-based and environmental sensing.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.