基于原位环境透射电子显微学的石墨烯传感器表面界面过程微观机制研究

Unveiling the sensing mechanism of micro-nano biochemical sensors is of great significance for developing new high-efficiency sensing element materials. This project combines the Cs-corrected environment transmission electron microscope and electrical holder with pico-ampere measurement accuracy to in situ observe the nanoscale surface/interface kinetic behaviors of graphene, MoS2 and SnS2 sensing element materials during the pre-concentration and specific detection of trace substances. The structural stability and morphological evolution of solid-vapor and solid-liquid interfaces under different polar environments will be investigated. Underlying physical nature underneath the infiltration/non-infiltration, surface passivation, adsorption/dissociation of sensing elements will be tentatively understood on the nanoscale, which will be beneficial to better unravel the process and mechanism of the biochemical reaction and energy exchange. Moreover, combining imaging simulation and first-principle calculation, this project will further explore the microscopic mechanism and strategy for functional modification of two-dimensional nanomaterials, and reveal the atomic-level structure and information associated with sensing performance modification. These will greatly help us optimize the surface and interface structure of sensing elements. The implement of the project will provide the theoretical and practical support for developing high-sensitivity, high-selectivity/-indentification, quick-response sensing element materials and devices that will be applied for detecting toxic and harmful substance dispersed in smog and haze atmosphere and polluted water.

从微观结构层面探寻微纳生化传感机理已成为研发新型高效敏感元件材料的有效途径。本项目采用带球差校正的高分辨环境透射电子显微镜(ETEM)并结合皮安精度的电化学测试平台，纳米尺度下原位动态观测汽液环境中石墨烯、MoS2、SnS2等二维纳米敏感元件材料在痕量靶标物质预富集以及特异性检测中的表面/界面动力学行为，研究材料固-液、固-汽界面在不同极性环境中的结构稳定性和形貌演变规律，尝试从纳米尺度认识浸润/非浸润以及传感元件表面钝化、吸附解离等现象背后的物理本质，揭示传感器生化反应和能量转换过程与机理；结合成像模拟和分子动力学原理计算，探索二维纳米材料功能化改性的微观机理和方法，揭示材料性能调控的原子尺度结构起源和信息，优化微纳敏感元件表面/界面结构。本项目的实施对研发面向雾霾、水污染检测的高灵敏度、高选择性/识别性、快速响应的高效敏感元件材料及其微纳传感器件具有重要的理论和实际指导意义。

基于高分辨球差校正电镜显微平台，采用新型固-液两相载样技术，在纳米尺度下实现了液体环境中金属离子预富集过程的观察，从纳米尺度上揭示了晶体界面生长行为的动力学本质。针对低维纳米材料和结构的表面界面动力学行为，利用原位电镜技术开展了固-固界面、固-液界面动力学行为研究以及材料界面尺寸（实际是界面缺陷）对材料性能的影响研究。利用高分辨透射电镜对纳米线与金属源以及纳米线与纳米线间的固-固界面金属离子传质行为进行了动态表征，获得了固-固接触界面离子传输过程中的结构相变过程，建立了固-固界面离子传输的相关物理模型。对于黑磷烯的制备，我们率先采用剪切剥离法制备出高质量的单层黑磷烯，并利用制备出的黑磷烯制作了湿度传感器，实现了湿度传感。课题共计发表带资助基金号61574034的论文31篇，其中SCI收录28篇，中科院一区论文19篇，影响因子大于10的文章12篇；课题负责人作为通讯作者和第一作者分别在Nature Nanotechnology, Nano Letters, ACS Energy Letters, ACS Nano, Nano Energy, Small Methods, ACS Appl. Mater. Interfaces, Carbon等期刊发表论文29篇。申请专利10项，目前已经授权5项。因此，本课题完成了预期的研究内容，超额完成了预期目标。