基于类石墨烯纳米涂层空芯微结构光纤传感机理及其在硫化氢监测中的应用研究

Hydrogen sulfide is the main pollutant of atmosphere and it is a kind of famous nervous gas. As the death ratio of occupational poisoning hazards ranks the first caused by the gas, it is urgent to produce the advanced sensitive materials and detection technology in order to resolve the serious security challenge from the rapid identification of low concentration (<10 ppm) and fast response (<10 s) for hydrogen sulfide. However, it is very difficult to detect the very low vapor concentrations of hydrogen sulfide. To solve this problem, in this work, a novel rapid chemical vapor sensor based on micro-structure fiber (MSF)with large air-holes coated with a sensitive graphene-like membrane (GLM) is proposed as a promising platform for rapid detection of the low concentration (<10 ppm)of hydrogen sulfide gas. The graphene-like nano-films WS2, MoS2 and doped nano-films are prepared by magnetron sputtering and ion sulphurizing technique. The graphene-like sensitive film is formed on the MSF cladding air holes. When hydrogen sulfide gas molecules flow through the large air-holes in the cladding of MSF, they are absorbed by the sensitive thin film to cause the change in the refractive index. The effect will result in a change in the effective index of cladding mode of the fiber, and hence, a shift in the resonant wavelength. In this subject, the sensing principle of MSF-GLM sensor with embedded sensitive film is analyzed. A great effort is made in study related to the fabrication of coatings deposited on the inner holes of MSF. An optofluidic assembly is designed to enable both gas flow and light transmission measurements through MSF-GLM structure optically coupled with single mode fiber. The all-fiber gas sensing system including MSF-GLM-based refractive index sensor is constructed and the capability of the MSF-GLM in rapid, selective, and sensitive detection of trace hydrogen sulfide can be achieved.

硫化氢是大气的主要污染物、是著名的神经毒气，由其导致的死亡率位列职业中毒的第一位，急需先进的敏感材料与检测技术以解决硫化氢超低浓度(<10ppm)快响应(<10s)所面临的安全挑战。但是超低浓度的硫化氢在气相很难被检测。提出一种基于类石墨烯纳米涂层(GLM)空芯微结构光纤(MSF)的气体传感新原理和方法，用于低浓度硫化氢气体快速探测。采用磁控溅射和离子渗硫法制备GLM，在空芯MSF包层空气孔中形成一层对硫化氢气体敏感的GLM，硫化氢分子能引起敏感膜折射率变化，并导致光纤包层膜有效折射率变化，通过实时观测光纤谐振波长变化，实现超低浓度硫化氢气体检测。项目在对“MSF-GLM”的气体传感原理研究的基础上，获取敏感物质在包层空气孔上成膜的方法；采用光流控技术设计光纤传感元件，建立基于MSF-GLM包层空气孔内敏感膜折射率变化的硫化氢气体传感新系统，以实现对硫化氢气体高灵敏、快响应、高选择性探测。

硫化氢是大气的主要污染物、是著名的神经毒气，超低浓度的硫化氢在气相很难被检测。在本项目的支持下，开展了以类石墨烯WS2和MoS2为典型代表的气敏特性和光纤传感技术相结合的研究，设计了新的硫化氢气敏光纤新传感器件。实验制备了类石墨烯MoS2和WS2纳米膜材料及复合材料体系。同时，通过控制微量掺杂物铜离子等修饰的类石墨烯MoS2和WS2的纳米组装,提升了硫化氢检测的特异性和灵敏度。明确了二硫化钨/钼因独特的气敏特性在材料表面吸附/解吸过程的电荷转移问题及其对气敏性能影响的微观机理。建立了光纤硫化氢传感测试系统；研究表明：在不同硫化氢浓度标准气体中，光纤气体传感器的灵敏度达到了皮米每百万分之一浓度（pm/ppm）、对硫化氢有强的选择性、好的响应速度和低的检出限、线性度可达0.97以上等；研究了温度、湿度等条件对光纤气体传感器的光谱及特征峰值波长的影响。在实用上，本研究结果对于及时获取掌握生产环境中硫化氢浓度信息、预测硫化氢浓度变化趋势、改善安全生产环境和防止毒气事故发生具有重要意义和作用；另外，本项目的研究方法、原理与技术还可拓展应用于其它气体的检测，如一氧化碳等。. 项目共取得64项成果：在《Sensors and Actuators B: Chemical》、《Applied Surface Science》、《Applied Optics》、《光学学报》等期刊上发表学术论文20篇，其中SCI论文11篇（IF>3.0论文6篇，含IF>5.0论文4篇）、EI论文7篇、中文核心1篇；申报专利11项（发明9项、实用新型2项），获权国家发明专利5项、实用新型2项；获软件著作权1项；邀请校外专家来课题组学术交流8人次、课题组成员外出学术交流25人次；培养研究生7名。