刺绣型碳纳米管-二维材料复合薄膜的制备与性能研究

One-dimensional (1D) carbon nanotubes and two-dimensional graphene, MoS2 are representative nanostructures with excellent properties; it is of significance but remains challenging to construct composite (or hybrid) systems combining the advantages of those materials. In this project, we will synthesize an embroidered composite film characterized by 1D-2D bicontinuous, mutually interpenetrated structure by chemical vapor deposition method, analyze the growth mechanism, and explore potential energy and environmental applications. Adopting a highly interconnected and conductive single-walled nanotube (SWNT) spiderweb network as the template, we will grow various 2D materials such as zero-bandgap graphene, semiconducting MoS2, and wide-bandgap BN, etc. in the network pores, and fabricate a series of composite films with controlled microstructure and tailored property. These SWNT network-embedded composite films are freestanding and integrate the mechanical and electrical properties from the 1D and 2D components, and also facilitate the film transfer to particular substrates and applications. The SWNTs also aligned into parallel and crossed configurations by mechanical combing, based on which we will analyze the nucleation and growth process of 2D materials within random or regular pores as well as the interface characteristics, and disclose the influence of key factors such as the pore shape and size on the growth behavior. Furthermore, we will transfer the composite films to crystalline silicon or other substrates and fabricate solar cells, flexible optoelectronic devices and gas sensors, and optimize the device performance. The project results will push forward the development and applications of high-performance nanocomposite structures.

一维碳纳米管和二维石墨烯、二硫化钼等纳米材料具有优良的性能；构建融合二者优势的复合体系具有科学意义和挑战性。本项目利用化学气相沉积法制备具有一维-二维双连续、互穿插结构特征的刺绣型复合薄膜，分析生长机制，并探索在能源和环境领域的应用。以高连通、高导电的单壁碳纳米管网络为模板，在网络孔隙中生长零带隙的石墨烯、半导体型二硫化钼、宽带隙的氮化硼等二维材料，制备一系列结构可控、性能可调的复合薄膜。这种由碳纳米管网络所支撑的复合薄膜结合了各组分的力学和电学性能，并为进一步的转移和应用提供了便利。采用机械梳理的方法使碳纳米管整齐交叉排列，在此基础上分析二维材料在无序或规则孔隙中的形核生长过程及界面特性，揭示孔隙形状、尺寸等关键参数对生长行为的影响。将复合薄膜转移到晶体硅或特定基底，制备太阳能电池以及柔性光电或气体传感器，优化器件结构和性能。研究成果将对高性能纳米复合材料的开发和应用起到推动作用。

碳纳米管与新兴半导体材料、二维材料及其它功能材料的复合是开发新型高性能光电能源器件、推进纳米技术实际应用和为社会经济发展服务的有效途径。本项目实施期间，团队成员合理分工，有效合作，围绕碳纳米管功能复合材料的可控制备及清洁能源应用这一目标开展系统研究。重要结果如下：基于高连通高导电的单壁碳纳米管薄膜及三维多孔碳纳米管海绵，采用液相旋涂、原位生长等方法制备了碳纳米管与金属氯化物、金属氧化物、石墨烯量子点、二硫化钼、金属有机框架等的多种复合薄膜和电极材料，应用于太阳能电池、锂离子电池、柔性传感器等前沿光电和储能领域。深入研究了高效率（>16%）、稳定性好的氯化物/碳纳米管/硅、氧化物/碳纳米管/硅、臭氧掺杂碳纳米管/硅等异质结太阳能电池器件，其中，金属氯化物和氧化物渗透到碳纳米管薄膜的孔隙内均匀复合，与碳纳米管协同作用共同优化电池结构和性能。通过结构表征和机理分析发现1）特定氯化物（如FeCl3, ZrCl4, SnCl2）及其组合功能层能够起到掺杂碳纳米管、增强内建电场、作为减反层等重要作用，2）两种氯化物（MoCl5, WCl6）热处理后转变为氧化物（MoO3, WO3）并对电池性能产生先衰减后提升的独特影响，3）合适程度的短时间臭氧处理能够调控碳纳米管的功函数进而增强界面势垒；这些揭示的机制优化了从光吸收到载流子分离和传输的全过程，有效改进了开路电压、短路电流和填充因子等关键参数，从而显著提高电池效率。项目成果在Solar RRL, Nano Research, Carbon, Adv. Energy Mater.等期刊发表代表性论文（5篇）及其它论文合计18篇，获授权专利2项，培养了数名研究生，其中2名博士毕业，1名硕士毕业。与哈尔滨工业大学、郑州大学等单位建立了密切合作。项目成员参加了NDNC，欧洲MRS等国内外学术会议和面向中学生的科普活动。项目研究的具有低成本高效率潜力的碳纳米管/硅太阳能电池作为新一代的硅基异质结光电器件，可能借助晶体硅电池的工业化技术，展示了良好的产业化和实际应用前景。