纳米多孔有机薄膜晶体管气体传感器的研究

Gas sensor based on organic thin film transistor (OTFT) possesses numerous advantages including low-cost, portable and convenient-operating. However, the response time of the OTFT based sensor is too long, which badly limited the development and application of such device. Aiming at this problem, OTFT-based gas sensor with nanoporous structure is proposed in this project, because such structure allows a large amount of gas molecules to rapidly access and interact with the OTFT conducting channel which is located on the bottom of the semiconductor layer. The research work of this project thus involves: fabrication of nanoporous organic semiconductor thin film by using self-assembled vesicle as template; investigation of the effect of nanoporous semiconductor layer on OTFT performance; and study of the effect of nanoporous structure on the performance of OTFT-based gas sensor. On the basis of the above work, this project is expected to provide with a simple, low-cost and controllable fabrication technology of nanoporous organic semiconductor thin film, understand the effect of nanoporous structure on the performance of OTFT and OTFT-based gas sensor, improve the response speed and sensitivity of the gas sensor, and finally realize the application of low-cost, rapid and portable gas detection in daily security and environmental issues.

基于有机薄膜晶体管的气体传感器具有低成本、轻量便携、检测便捷等优点，但目前制约该传感器发展与应用的主要瓶颈在于其对分析物的探测响应时间太长。针对上述问题，本项目拟利用纳米多孔结构具有高比表面积，允许气体分子快速大量通过的优点，开展基于纳米多孔结构的有机薄膜晶体管气体传感器的研究。具体包括，以两亲性分子自组装囊泡为模板的纳米多孔有机半导体薄膜的溶液法制备研究；有机薄膜晶体管中半导体层的纳米多孔结构对晶体管性能的影响；以及纳米多孔结构对有机薄膜晶体管气体传感器探测性能的影响。基于上述研究，可望提供一种简便低成本的纳米多孔薄膜可控制备方法，掌握半导体的纳米多孔结构对有机薄膜晶体管性能，以及基于此的气体传感器性能的影响，提高该传感器的响应与回复速度及灵敏度，推动实现对日常生活中环境安全等问题快速便携低成本检测的应用。

相对于其他类型的气体分析探测装置，基于有机薄膜晶体管（OTFT）的气体传感器在器件具有低成本、轻量便携、检测便捷等天然优势。然而，目前 OTFT气体传感器的应用仍面临着一些瓶颈问题，包括对目标分析物的灵敏度与响应速度不足。本项目面向上述问题，开展了多孔有机半导体薄膜的制备研究，有机薄膜晶体管中半导体层的多孔结构对晶体管性能的影响，以及多孔结构对有机薄膜晶体管气体传感器探测性能的影响研究。掌握了有机半导体纳米多孔薄膜的制备工艺及条件参数，制备了纳米多孔结构有机半导体薄膜；了解了纳米多孔结构对OTFT器件性能的影响，相较于传统的基于有机半导体DNTT的OTFT，多孔器件的输出电流降低了约5倍；掌握了纳米多孔结构对OTFT气体传感器性能的影响，传统DNTT-OTFT对NH3的相对灵敏度为20% ppm−1，而多孔器件达到340% ppm−1，提高了17倍，传统DNTT-OTFT对0.5 ppm NH3的响应时间大于100 s，而多孔器件产生同等程度响应的时间小于10 s，提高了超过10倍。在此基础上，还开展了有机半导体薄膜与聚苯乙烯微球共混对OTFT光电探测性能的影响；蒸镀工艺调控的有机半导体薄膜的晶粒尺寸对OTFT气体传感器性能的影响；柔性OTFT的聚合物介质层引入的界面效应对器件性能与其光电探测性能的影响机理等相关研究。通过上述工作，揭示了OTFT传感器的性能影响机制及机理，提供了一系列提高OTFT传感器性能的方法策略。