功能化石墨烯气体传感器多气氛检测技术及敏感机理

Due to the oxidizability of graphene and the reducibility of graphene oxide, the structure of product would be of different oxygen-containing functional groups. The different oxygen-containing functional groups could affect the sensitivity and selectivity of the adsorbed gas. To detect and monitor the multi-component gas mixture in narrow confined spaces, this project will study on how to prepare the functionalized graphene with certain unique moiety in a controllable way, how to design and integrate the functionalized graphene gas sensor with FET structure, and how to analyze the characteristic spectrum lines, et al. Besides, compositions, structures and performances of functionalized graphene were characterized with a variety of modern analytical techniques. The molecular dynamics simulation and the first-principle calculation are applied to investigate the process of adsorption kinetics and the selective mechanism. In the process of studying the project, it is predictable that the relationship of resistance with temperature, resistance with gas concentration, and sensitivity with response and recovery time will find out. The database of characteristic spectrum lines about the resistance variation as the gas concentration changing will be built as well. It will reveal the intrinsic response nature and the trace perception mechanism of sensitive materials (functionalized graphene) on different gas. Moreover, this study will make breakthrough on the preparation and miniaturized integated technology of FET gas-sensor based on the functionalized graphene materials. It will contribute to set up the analytic method on multivariable polynomial system of characteristic spectrum lines and the theoretical calculation model. Additionally, the purposes of detection and real-time monitoring types and contents of various gases will be achieved.

针对密闭狭小空间的多气氛检测与监测问题，基于石墨烯的可氧化性和氧化石墨烯的可还原性及不同含氧官能团对气体的敏感性和选择吸附性，研究不同含氧官能团占优势的GO和rGO的可控制备、FET气敏元件设计和FG气敏传感器集成技术及多气氛特性谱线解析方法等；采用多种现代分析测试技术对FG气敏材料的成分、结构和性能及传感器的气敏性能进行表征；采用分子动力学模拟和第一性原理方法研究气体分子的吸附动力学过程和选择性机制；获得不同FG气敏材料阻温性能、电阻率－气体浓度和灵敏度－响应－恢复时间曲线及稳定性，以及不同FET元件对单一和多气氛气体电阻率随浓度变化的标准特性谱线数据库；揭示FG气敏材料对不同气体响应的内在本质及多气氛痕量感知的指纹特征产生机制；突破FG气敏材料的FET设计、制备及小型化集成技术；建立多气氛特性谱线多元方程组联立解析方法与理论计算模型；达到对多气氛气体种类和含量变化实时检测和监测目的。

针对密闭狭小空间的多气氛检测与监测问题，基于石墨烯的可氧化性和氧化石墨烯的可还原性及不同含氧官能团对气体的敏感性和选择吸附性，研究了不同石墨烯基气敏材料的可控制备方法和对目标气体的气敏相应，并利用量子化学计算揭示了材料对不同分子的选择相应机制；建立了多气氛特性谱线多元方程组联立解析方法与理论计算模型；达到对多气氛气体种类和含量变化实时检测和监测目的。结果表明，环氧型氧化石墨烯中的环氧基相对含量可达21.65%，增加环氧基的量可提高对湿度的选择性，在湿度为93.6%RH，最大灵敏度可达86.6%。羟基型氧化石墨烯对100ppm浓度的氢气具有一定的响应，其最大灵敏度可达21.3%。且在180℃下，Pd掺杂Fe2O3/氧化石墨烯传感器对H2的灵敏度最高，当H2浓度为50 ppm时，灵敏度达47%，当H2浓度为1000 ppm时，灵敏度为78.4%，响应时间为19 s，恢复时间为6 s。不同官能团对气体分子的响应主要受氢键作用和π键作用影响。