钙钛矿型太阳能电池真空制备原位实时表征

Perovskite solar cells (PSCs) have great potential due to their simple device structure, lost cost and excellent power conversion efficiency. However，there are still problems to be solved such as the poor reproducibility, the unsatisfied device stability, as well as the lack of through understanding of their physical mechanism. Therefore, it is urgent to study the fabrication of the PSC materials as well as the PSC devices thoroughly for further enhancing PSC performance. The proposal will focus on the planar PSCs prepared under vacuum condition. First, we will make use of in-situ real time synchrotron X-ray Diffraction and Scattering techniques to investigate the fabrication process of the Perovskite film to reveal how the different approaches influence the microstructure, morphology as well as the kinetics of perovskite film formation and crystallization. Similarly, different layers’ fabrication processes will be investigated as well. All these synchrotron based study will be used to guide improving the fabrication process of the PSC materials and devices. Second, in-situ photoemission spectroscopy will be conducted to investigate the chemical composition and electronic structures of the PSC materials during its growth as well as to characterize the interfacial electronic structures in the PSC devices. Combing with the performance characterization of PSC devices prepared using different conditions, this study will help to understand better the relationship between device performance and the formed microstructure, morphology as well as the interfacial electronic structures in the PSC devices. This eventually will help to optimize the fabrication process of high performance PSC for the market.

钙钛矿太阳能电池成本低廉、能量转化效率高，具有极大的应用潜力。目前钙钛矿太阳能电池还存在制备重复性差、器件稳定性以及工作机理理解不深入等问题，亟需对钙钛矿材料和器件制备开展深入研究。本项目将集中研究平面钙钛矿太阳能电池的真空原位制备，重点利用同步辐射X射线衍射和散射技术对钙钛矿薄膜的制备进行原位实时观测，揭示不同条件对薄膜结构与形貌以及薄膜形成的反应动力学及结晶动力学的影响，也对钙钛矿太阳能电池的传输层和电极层开展原位研究，基此来指导优化薄膜材料和器件的制备工艺。另一方面，将采用光电子能谱技术对钙钛矿薄膜生长的不同阶段化学成分和电子结构变化、不同层界面的电子结构进行原位表征。结合不同工艺平面异质节钙钛矿太阳能电池的器件性能测试，将全面深入理解器件性能与其不同制备条件导致的材料微结构、形貌以及薄膜界面电子能级结构的关系，最终指导优化钙钛矿太阳能电池制备工艺以推动其产业化进程。

钙钛矿太阳能电池成本低廉、能量转化效率高，具有极大的应用潜力。目前钙钛矿太阳能电池还存在制备重复性差、器件稳定性以及工作机理理解不深入等问题，亟需对钙钛矿材料和器件制备开展深入研究。为此，一方面我们在基金的支持下建立了一套真空原位系统，可以实现真空双源蒸发沉积法制备钙钛矿薄膜以及电荷传输层和电极层的蒸镀，既可以利用光电子能谱观测蒸镀过程中的电子结构变化，也可以在上海光源衍射线站进行掠入射X射线衍射（GIXRD）的原位蒸镀研究，观测其中的微结构演变。利用该装置，我们开展CsPbI2Br的蒸镀和退火原位光电子能谱以及GIXRD的研究，发现衬底加热对钙钛矿形成与结晶决定性影响的初步结果，有利于指导高质量的无机钙钛矿薄膜。另一方面，系统的摸索溶液法生长钙钛矿的多种制备和处理工艺，并进行钙钛矿薄膜的原位及非原位GIXRD同步辐射表征研究，专注与薄膜的构效关系，同时指导优化器件制备，主要一些工作包括原位研究退火过程中薄膜微结构的演化，发现了退火过程中的重结晶现象，进一步研究不同退火方式对钙钛矿薄膜微结构的影响，采用渐进式退火提高薄膜表面的相结构纯度，器件的效率也大大提升；开发了一种钙钛矿太阳能电池薄膜“缺陷快速补偿”工艺，原位实验证明薄膜表面结晶得到有效钝化，大幅提升电池效率达到~20%；用红色碳量子点（RCQs）掺杂低温溶液加工的SnO2，使SnO2的电子迁移率大幅提升，钙钛矿太阳能电池效率达到22.77%；采用钙钛矿作为自旋传输介质，利用自旋泵浦测量反自旋霍尔效应测量了在CH3NH3PbCl3-xIx钙钛矿的自旋传输距离为~61纳米，在此基础上成功制备了自旋阀器件，在温度为10K下取得了0.57%的磁阻。总之，我们在项目支持下的工作成果显著，有利于最终指导优化钙钛矿太阳能电池制备工艺以推动其产业化进程，而且我们还将研究拓展到钙钛矿自旋器件。