基于柔性Mo衬底的无Cd环保型Cu2ZnSnS4薄膜太阳电池研究

Solar cells with high efficiency, low-cost, friendly-environment and portability will be an important research direction in the future. In this proposal, our object is to develop flexible and environment-friendly Cu2ZnSnS4 (CZTS) thin film solar cells without toxic Cd. Based on flexible Mo foil substrates and Cd-free Zn(O,S) buffer layers, the preparation and photovoltaic properties of CZTS/Zn(O,S) heterojunctions and solar cells will be investigated. CZTS and Zn(O,S) films with variable O/S ratio will be deposited successively on the Mo foil substrates by sol-gel method and chemical bath deposition and then sulphurization (or annealing) to obtain CZTS/Zn(O,S) heterojunctions. The influences of preparation process on the constitutes, micro-structures and photoelectrical properties of the CZTS/Zn(O,S) heterojunctions will be explored. The interfacial characteristics, energy band diagram, transportation mechanism and effective collection of the carriers in the CZTS/Zn(O,S) heterojunction will be clarified. By combining the theoretical simulation with the experimental exploration, the internal relations among the fabrication process, device structures, surfaces, interfaces, physical parameters, and the photovoltaic performances of CZTS solar cells will be revealed in order to obtain flexible and Cd-free CZTS solar cells with an efficiency larger than 5% . The research result will be of important scientific significance for developing new types of green and environment-friendly solar cells.

高效、廉价、环保、便携的太阳电池将是未来发展的重要方向。本项目拟以柔性无Cd环保型Cu2ZnSnS4（CZTS）薄膜太阳电池为研究目标，提出以柔性钼箔为衬底和以Zn(O,S)为缓冲层，研究CZTS/Zn(O,S)异质结及其太阳电池的制备工艺和光电性能。拟利用溶胶凝胶法和化学浴法与热处理工艺相结合在柔性Mo衬底上先后制备CZTS和O/S比例可调的Zn(O,S)薄膜，构建CZTS/Zn(O,S)异质结，探究薄膜的制备工艺对该异质结的组成、微结构和光电性能的影响规律，阐明该异质结的界面特性、能带结构、载流子输运和有效收集等相关问题。将理论模拟与实验研究相结合，揭示CZTS太阳电池的制备工艺、表面、界面、膜层结构和物理参数与其性能的内在联系，以期获得效率高于5%的无Cd柔性CZTS太阳电池，研究结果对发展新型的绿色环保太阳电池将有重要的科学意义。

高效、廉价、环保、便携的太阳电池将是未来发展的重要方向。本项目以柔性无Cd环保型Cu2ZnSnS4（CZTS）薄膜太阳电池为研究目标，对Zn(S,O)、In2S3等缓冲层的制备与掺杂改性及其与CZTS形成的异质结（如Zn(O,S)/CZTS、In2S3/CZTS等）带阶进行了系统研究；用SCAPS仿真了分别以Zn(S,O)和In2S3作为CZTS太阳电池的缓冲层时，电池性能与其膜层结构和物理参数之间的相互关系，获得了优化条件下相关的物理参数；对结构为SLG/Mo/CZTS/In2S3/i-ZnO/ZnO:Al的CZTS太阳电池，在优化条件下其效率可达19.28%。用Ag+微量取代Cu+，在柔性Mo衬底上研制了(Cu1-xAgx)2ZnSnSe4(CAZTSSe)太阳电池，其效率从4.34%提升至6.24%，且开压损耗减少了67mV；通过进一步优化硒化条件获得致密、结晶良好的CZTSSe薄膜，制备出转化效率为6.78%的高柔性CZTSSe太阳电池。阐明了异质结中的界面特性、带隙匹配、异质结过渡、载流子输运和有效收集、以及界面复合机理等相关问题。发表学术论文20篇，全部被SCI或EI收录，授权发明专利10件，培养了研究生6人，出席国内和国际重要学术会议15人次。