SnS2微/纳米结构多孔阵列薄膜的可控构筑及其气敏特性研究

Layered two-dimensional SnS2 material is considered to be one of the most promising materials for gas sensing application, due to its merits of proper bandgap, low cost, and environment-friendly harmlessness. In order to give full play to its gas-sensing properties, considerable efforts have been devoted to downsizing the layered SnS2 materials to nanoscale and low dimension over the past few years, but it will also bring serious challenges to its structural and performance stability. Therefore, how to balance the high activity and stability of SnS2 nanosheets is one key scientific problem that must be solved for their gas sensor design and practical application. In this project, based on monolayer colloidal crystal template, we intend to in situ synthesize SnS2 micro/nanostructure porous array films on sensing electrode substrates with the solution-dipping and template-transfer strategy, and then will study its gas sensing characteristics. It mainly includes: the construction of micro/nanostructured porous array thin films as well as their structural parameters optimization (ordered pore arrangement period, number of layers, composition, etc.); elucidation of the evolution of micro/nanostructure characteristics with process parameters; exploring the relationships between the micro/nanostructure characteristics, material compositions, interface electronic states and thin-film gas sensing properties; revealing the sensing enhancement mechanism with micro-nano structure coupling as well as the gas selective mechanism, which will provide us a new reference in material science for the design and application of metal sulfide micro/nanostructured array gas sensors.

二维SnS2层状材料具备合适带宽、成本低廉和环保无害的特质，是一种极具应用潜力的气敏材料。为了充分发挥其气敏特性，学术界近年来一直在探索SnS2片层的纳米化和低维化途径，但在此过程中却带来了对其结构和性能稳定性的严重考验。因此，如何兼顾SnS2纳米片层的高活性和稳定性是相应气敏器件设计和应用亟待解决的关键科学问题。本项目拟以单层胶体晶体为模板，基于溶液浸渍-模板转移策略，在传感电极衬底上原位合成SnS2微/纳米结构多孔阵列薄膜，研究其气敏特性。主要包括：微/纳米结构多孔阵列薄膜的原位构筑及其结构成分参数优化（孔排列周期、层数、成分等）；阐明其微/纳米结构特征随工艺参数的演变规律；探究薄膜气敏特性与微/纳米结构特征、材料组分及界面电子态之间的关联关系；揭示其气敏特性的微-纳结构耦合增强机制及选择性传感机理，为金属硫化物微/纳米结构阵列气敏器件的设计和应用提供材料学参考。

本项目针对金属硫化物纳米片层气体传感的高活性、高选择性和稳定性难以兼容问题，分别从结构形态、表面缺陷、元素掺杂、异质界面等多种角度，优化制备出多种SnS2纳米结构阵列并系统研究了其气体传感特性，实现了对常见大气污染物的高性能传感，提出了硫化物表界面路易斯酸碱度对气敏特性的调控新机制。在结构形态调控方面，采用胶体晶体模板法等关键技术首次构建了SnS2微/纳米分级结构大孔阵列薄膜，实现了对H2S气体的高灵敏、快速（10s级）与长效稳定检测，探究了其有序大孔结构增强敏机制；在缺陷调控方面，基于等离子体辐照技术，构建了富含表面S空位缺陷的SnS2片层阵列，低温下实现了高NH3灵敏度(200 ppb)、强选择性与快速响应回复速率，研究了硫空位缺陷对其电子结构及其NH3气敏特性的影响，阐明了二维金属硫化物气敏性能的基面激活效应；在异质原子掺杂方面，通过前驱体溶液调控等方法，实现了对金属硫化物的Mo金属元素与O非金属元素掺杂，研究了异质原子对其电子受给特性及其气敏性能的影响并揭示了其掺杂增敏机制，分别实现了对碱性NH3气体与酸性NO2气体的高性能检测，首次发现了二维金属硫化物的P-N传感转变现象，为气体选择性检测提供了更为直接有效的实现途径；在界面调控方面，借助于p型黑磷的空穴注入效应，有效抑制了低价的Sn2+、硫空位及其表面路易斯酸性，实现了对ppb级酸性NO2气体的低温快速稳定识别，结合理论计算和原位光谱揭示了其化学吸附增强机理。本项目研究阐明了金属硫化物薄膜成分结构耦合增敏机制与选择性调控机理，为新型高性能气敏器件提供新的设计思想与材料学参考。本项目在国内外知名期刊上发表了学术论文25篇（影响因子大于10的论文12篇）；申请了中国发明专利8项，其中授权7项；培养了博士生1人，硕士生3人；参加学术会议9次。