掺杂类金刚石（DLC）薄膜的微结构与其光电性能的定量关系研究

Diamond-like carbon (DLC) film is one of the ideal materials to replace the traditional transparent conductive ITO film, because of it's excellent mechanical, photoelectric and other properties. The microstructure of sp2 is considered to dominate its photoelectric properties of DLC films, so that the effective quantitative analysis of its microstructure is the key to study their photoelectric properties. Due to the lack of research on the quantitative analysis of different hybrid forms of carbon and the presence of hydrogen in the microstructure of DLC films, DLC film has not yet achieved the unification of transparent conductivity. Element doping is considered to be an effective way to regulate the microstructure of DLC film, in this project, magnetron sputtering and microwave plasma enhanced CVD deposition techniques will be used to obtain the necessary hydrogen/non-hydrogen DLC films by controlling the doping components (typical carbides forming elements such as W, Nb and semiconductor-doped nonmetallic B, N, etc.) and parameters. The near edge X-ray absorption fine structure, Rutherford backscattering/Elastic recoil detection analysis, and other analytical methods will be used to quantitatively analyze the microstructure of doped DLC films that cannot be achieved by traditional analytical methods. Then, we can reveal the effect of elemental doping on the microstructure, determine the quantitative relationship between the microstructure and photoelectric properties, and realize the controllable preparation of DLC films with preset photoelectric properties. These results will lay a theoretical and experimental foundation for the development of transparent conductive properties of DLC films.

DLC薄膜因具备优异的机械、光电等诸多特性，是替代传统透明导电ITO薄膜的理想材料之一。DLC微结构中sp2杂化碳被认为主导了其光电性能，因此微结构的有效定量分析是研究其光电特性的关键。由于DLC微结构中碳的杂化形式和氢的定量分析缺乏研究，目前DLC薄膜仍未实现透明导电的有机统一。元素掺杂是调控DLC薄膜微结构的有效方法，本项目采用磁控溅射和微波等离子CVD技术，选择典型的碳化物形成元素（W，Nb等）和半导体掺杂（B，N等）元素，通过控制掺杂组元和参数获得所需含氢/非氢DLC薄膜。然后利用近边X射线吸收精细结构、卢瑟福背散射/弹性反冲分析等方法，实现传统分析手段未能达到的掺杂DLC薄膜微结构的定量分析。从而，揭示元素掺杂对DLC薄膜微结构的影响规律，确定DLC薄膜的微结构与光电特性间的定量关系，实现预设光电特性DLC薄膜的可控制备，为发展DLC薄膜的透明导电性能奠定理论与实验基础。

本项目针对类金刚石（DLC）薄膜光电特性，开展了基于磁控溅射等物理化学气相沉积技术通过元素掺杂等条件控制合成不同类型DLC薄膜。发现DLC在不同沉积条件下，其外观颜色可发生有规律的变化，对不同氢含量类金刚石薄膜进行了结构色的深入研究，结合理论计算等手段，结合薄膜干涉和非晶光子晶体结构色等理论，初步探究了DLC薄膜的结构色光学特性的显色机理。另外，针对DLC薄膜的电化学性能，DLC薄膜沉积在铝箔负极表面，作为铝基负极双离子电池的人工SEI膜，发现电池副反应得到了有效抑制，原本厚达800 nm的天然SEI膜，在使用DLC人工SEI改性后，其反复形成得到有效抑制，降低到23 nm，铝负极得到了有效保护，电池循环稳定性得到有效改善。相关研究拓展了DLC薄膜在电化学领域的应用，为研究DLC薄膜的电化学特性以及基于铝等合金化负极的工业化应用提供理论支撑。同时，将DLC薄膜沉积在聚丙烯隔膜表面，高模量DLC复合隔膜在锂金属电池中发生原位锂化现象并对锂枝晶起到了抑制作用，随后团队通过一系列实验和理论计算初步验证了DLC原位锂化的产生原理。在锂锂对称电池稳定循环达到4000圈以上，在锂磷酸铁锂电池以及高面密度（8 mg/cm2）锂三元正极全电池中也实现了1000圈和250圈以上的稳定循环，DLC隔膜改性在锂金属电池锂负极改性策略的有效性得到了有效验证，相关研究为开发高性能的锂金属电池提供有效途径，将为推动锂金属电池实用化提供重要支撑。