胶体量子点室温气体传感器的性能调控及机理研究

With the increase of economy development and environmental protection consciousness, the low-cost and high-efficiency detection of ppb-level toxic gas has become the focus of our society. Room-temperature semiconductor gas sensors possess the ease of integrating and networking. Nevertheless the manipulation of their gas adsorption activity and charge transport remains challenging for its application. Based on our prior work, this project will design and develop room-temperature gas sensors by employing colloidal quantum dots (CQDs), a highly tunable material with extremely small crystal size and superb room-temperature processability. Specifically, we will control the point defects and surface states of SnO2 and PbS CQDs through the control over their composition, crystal size, morphology and the lattice plane, and through the surface modification introduced in CQD solutions and films. We will approach suitable gas adsorption activity with higher electron transfer and transport capabilities through the optimization of device structure and interface by employing heterostructures and porous microstructure, electrode design and hydrophobic surface filter. We will also conduct a comprehensive study on the physical and chemical properties of the CQD sensing layer under real gas atmosphere using electrical, opto-electronic and optical characterization methods and theoretical calculation to elucidate the gas-sensing mechanism by building a theoretical model detailing the mechanisms of charge generation, transfer and transport. The goal is to achieve a balance between the response activity and the recoverability and stability, and hence develop high-performance CQD gas sensors capable of detecting ppb-level gases such as NO_2 and SO_2 at room temperature.

随着经济发展和环保意识的提高，ppb级低浓度毒害气体的低成本高效检测成为社会关注的焦点，室温半导体气体传感器具有易于集成和组网的特点，如何对其气体吸附活性和载流子传输特性进行合理调控是亟待突破的关键科学问题。本项目拟在前期工作基础上，利用胶体量子点晶粒细小、室温成膜性好且物化特性可控的特点，通过氧化锡、硫化铅等胶体量子点的可控合成与表面修饰，调节量子点组分、尺寸、形貌和晶面结构来控制点缺陷和表面态，采用气敏层异质复合与多孔化、电极设计和表面疏水滤透膜等手段优化传感器各功能层结构及界面，使之对目标气体具备合适的吸附活性和更高的电荷转移及传输能力，尝试利用电学、光电和光学原位表征分析量子点物化特性随气体的变化并辅以理论计算，围绕电荷产生、转移和传输建立理论模型阐明室温气敏机理，突破协同调控传感器室温气敏响应活性与恢复特性以及稳定性的关键技术，获得适于ppb级NO2和SO2等检测的室温传感器。

室温半导体气体传感器研究对于发展高灵敏、低功耗气体检测技术具有重要意义。本项目提出利用胶体量子点晶粒细小、室温成膜性好且物化特性可控的特点构建新型室温气体传感器。围绕传感器气体吸附活性与载流子传输特性的合理调控这一核心科学问题，研究并掌握有效调控胶体量子点气体传感器性能的关键技术和机理，设计并制备出适于检测ppb级毒害性气体的室温气体传感器。主要研究结果：（1）研究并掌握SnO2、PbS等胶体量子点可控合成与表面修饰技术，结合传感器各功能结构与界面的优化，设计并制备出适于ppb级NO2、H2S等气体检测的室温气体传感器；（2）以系统的实验为基础，结合电学、光电和光学等原位表征分析并辅以理论计算，建立了传感器理论模型，从电荷产生、转移和传输的角度初步阐明量子点室温气敏机理，为室温气体传感器的设计与制备提供了理论参考。通过本项目的研究，构建出基于胶体量子点气敏效应的新型传感器，拓展了低功耗半导体气体传感器研究体系与技术途径，为发展支撑新一代环境物联网和人工嗅觉系统的智能气体传感器打下了基础。相关研究结果以项目负责人为第一或通讯作者发表SCI论文11篇（第一标注7篇），申请中国发明专利4项（1项已授权），培养毕业博士2人、硕士5人。项目负责人受邀在国内外作相关学术报告6次，组织国际会议2次；2017年获第12届亚洲化学传感器大会（ACCS）青年科学家奖，2019年获得国家优秀青年科学基金项目。