室温超高灵敏度响应的导电高分子/ZnO复合纳米纤维气敏材料和气体传感器

Core-sheath structured porous composite nanofibers of p-type polyaniline (polypyrrole) and n-type ZnO are prepared by using coaxial electrospinning and heat treatment, and control on the composition, structure, morphology of the composite nanofibers and properties of p/n junction formed at the core-sheath interface are realized. Gas sensors are in-situ constructed by depositing composite nanofibers on interdigitated gold electrodes. The composite nanofiber gas sensors exhibit greatly enhanced sensitivity, accelerated response and room temperature sensing, which is attributed to large surface area to volume ratio and decreased interface barriers of the composite nanofibers, and great variations in the properties of the p/n junction upon interactions with target gas. Moreover, the stability of the gas sensors is improved by formation of crosslinked structures via interactions between nanofibers and underlying gold electrode substrate. Sensing properties of the composite nanofibers towards ammonia and other gases at room temperature are investigated, and correlated with the composition, structure, morphology and properties of p/n junction of composite nanofibers. High performance resistive-type gas sensors with prominent advantages including ultrahigh sensitivity, fast response, good stability and room temperature response are prepared by optimization of the gas sensing materials of the composite nanofibers and the configuration of the electrodes. Gas sensing mechanism is clarified, and the theoretical model is established, thereby providing guidance for the development of high performance gas sensing materials and gas .sensors.

采用同轴静电纺丝及热处理等方法，制备多孔核鞘结构的p型聚苯胺、聚吡咯等与n型ZnO复合纳米纤维气敏材料，实现复合纳米纤维的组成结构、形貌及核鞘界面形成的p/n结特性的可控性。在叉指金电极上沉积复合纳米纤维，原位构建电阻型气体传感器。利用多孔纳米纤维大的比表面积和低的晶界势垒，特别是吸附气体作用导致界面p/n结特性变化等，极大提高复合纳米纤维气体传感器的响应灵敏度，加快响应，实现室温检测；通过纳米纤维与叉指金电极基底作用形成交联结构，提高稳定性。研究复合纳米纤维气敏材料在室温下对氨气等的响应特性，揭示其组成结构、形貌、p/n结特性等与敏感特性的关系。优化复合纳米纤维气敏材料、电极结构等，制备对氨气等具有超高灵敏度、响应快、稳定性好及室温响应等优点的高性能电阻型气体传感器。阐明气敏响应机理，建立理论模型，为研制高性能气敏材料和气体传感器提供理论依据和借鉴。

研制灵敏、快速和特异性检测气体的气体传感器，在环境检测和保护，工业生产过程控制、国防和反恐等领域有着重要意义和良好应用前景。本研究设计制备纳米结构ZnO等无机半导体氧化物及其与导电聚合物纳米复合物，利用两者的协同效应和纳米效应，构建具有室温超高灵敏度响应的高性能气敏材料和气体传感器。通过研究，已完成预期目标，提出并建立了一种新的静电纺丝结合水热处理的方法，采用低温水热处理含醋酸锌的静电纺丝纳米纤维，原位制备ZnO纳米片和纳米粒子。该方法避免了传统的高温灼烧方法及纳米材料的二次分散和沉积，具有绿色环保优点，可用于在各种基底原位沉积纳米结构ZnO，制备纳米复合气体传感器等光电功能器件。通过气相和溶液聚合，及浸涂可分散聚苯胺等方法，在原位沉积的纳米结构ZnO表面覆盖导电聚合物，制备了与电极基底具有良好欧姆接触的复合气敏材料，构建了电阻型气体传感器。考察了静电纺丝、水热处理及聚合条件等对复合物组成、结构和形貌、界面p/n结特性等的影响。研究了ZnO与导电聚合物纳米复合气体传感器对氨气的室温响应特性，探讨了气敏材料的组成、结构、形貌特性等与其响应特性的关系。ZnO纳米片与气相聚合苯胺的复合物对氨气具有室温超高灵敏度响应（对10 ppm氨气，其电阻相对变化为2150%）和极低检测限（~ 5ppb），同时体现优异的选择性、良好的回复性和重现性，是一类高性能有机/无机纳米复合气敏材料和气体传感器。探讨了ZnO与导电聚合物纳米复合材料的气敏响应机理，提出复合物界面形成的p/n结，及纳米结构和形貌特性等与其优异的气敏响应特性相关。该方法具有普适性，可原位制备纳米结构二氧化锡、二氧化钛及氧化铁等与聚苯胺、聚吡咯等系列复合气敏材料和气体传感器，其对氨气等均具有室温高灵敏度、高选择性的优异气敏响应特性。研究将为高性能有机/无机半导体氧化物纳米复合气敏材料和气体传感器的研制提出新的途径和有益借鉴。