Chemical Sensing Platform to Accelerate Real-World Interfacing
Chemical sensing technology has been the most valuable engineering field in current and future society due to its ability to detect invisible chemical molecules and predict and alarm future accidents. Performances of the chemical sensor have been greatly improved but there is still long-standing gap between commercial devices and field-required performances of chemical engineering. We are interested in a breakthrough in bottlenecks of conventional chemical sensor technology by leveraging state-of-the-art nanotechnology and channel fabrication technology, and eventually, hope to accelerate the real-world interfacing of chemical sensors.
We have designed and controlled the whole stage of the solid-state sensor development/fabrication loop: From channel material selection - surface chemistry & nanostructure design - device integration & measurement - to signal analysis using machine learning and mathematical model. With this nanotechnology-leveraged sensor design feedback loop, we have developed high-performance chemical sensors with superior response time, sensitivity, selectivity, and applied those to various targets including human, industry, environment, and vehicle monitoring.
1) Top-Down Nanolithography Process for Commercial-Level Sensor Fabrications
We have proposed and developed a new concept of large-area (4-inch wafer scale) and high-resolution (10-15 nm) nanochannel fabrication technique with various material compositions (metal, oxide, heterojunction, doping) and applied into versatile gas sensing devices - hydrogen or volatile organic compounds (Anal. Chem. 2015, Nano Lett. 2016, ACS Sens. 2018, Sensors 2018, Adv. Funct. Mater. 2019, Anal. Chem. 2019, Adv. Mater. 2019, Adv. Funct. Mater. 2020). With top-down approach of nanolithography process, multivariate nanosensing channels could be fabricated and integrated with electronic sensing devices with low device-to-device variations. The patent on this platform has been technology licensed to SENSOR TECH Inc. with the royalty.
2) High-Throughput Production of Sensing Materials
We have designed and synthesized versatile low-dimensional (1D, 2D) chemical sensing materials (CNT, graphene, 2D materials (TMD, Black phosphorous), carbide) for selective target analyte monitoring by controlling their nano-micro structure and surface chemical properties (ACS Nano 2015, Adv. Mater. 2016, ACS Sens. 2017, Chem. Mater. 2017, ACS Sens. 2018, ACS Appl. Mater. Interfaces 2018, J. Mater. Chem. A 2018, ACS Appl. Nano Mater. 2019, ACS Nano 2019, Anal. Chem. 2020). In addition, we have integrated those sensing materials with continuous and large-batch scale production systems such as liquid crystal (LC) based wet spinning process, liquid exfoliation, and wafer-scale CVD process, so that we successfully showed wearable and mechanical strength real-world application sensor [NEWS].
3) Large-Area Plasmonic Substrates for Biosensing
Optical plasmonic substrates with meta-nanostructures have been widely used in various bioanalytes and in-situ cellular monitoring. However, their performances and applications have been limited with low-resolution of plasmonic nanostructures and small-area fabrication. We have developed high-resolution (10-30 nm) plasmonic sensing substrate enabled by large-area top-down lithography on versatile functional substrates (Adv. Funct. Mater. 2014, Nano Lett. 2015, ACS Appl. Mater. Interfaces 2018). We controlled the interface, components, and scale of cell-nanopattern and transducer-nanopattern hybrids in precise resolution. With that plasmonic enhanced spatial control, we successfully enhanced the optical sensing properties of nanotransducers and controlled the neurogenesis of the human neural stem cells (hNSC) in large and easy way.