基于可交联添加剂的钙钛矿电池及其连续功率输出下的稳定性研究

Device stability, especially the operational stability under continuous power output, is a major bottleneck limiting the commercialization of perovskite solar cells (PSCs). One of the major reasons for stability issue in PSCs is the ions migration in perovskite film. Recently, we propose an in-situ crosslinking strategy to fabricate efficient and stable PSCs through the incorporation of crosslinkable additives. This additive can chemically anchor to and then crosslink at grain boundaries (GBs) in perovskite films, thus blocking the channels for ions migration. As a result, the ions migration is effectively limited in crosslinked perovskite films. The resulted PSCs exhibit good stability after continuous power output for 400 hours, which is 590 times larger than control PSCs. This work indicates that it is an effective method to improve the operational stability of PSCs through in-situ crosslinking strategy with crosslinkable additives. However, the working mechanism behind stability improvement still needs to further in-depth investigated. This project aims to fabricate operationally stable PSCs after aging over 1000 hours thorough developing new crosslinkable additives and corresponding processing methods. In this project, we plan to investigate how devices efficiency and stability vary with different additives and processing methods. Throughout this project, we will in-depth understand the relationship between devices performance and additives' chemical structure, introducing approaches or crosslinking methods. We believe our project will provide new insights and methods for the fabrication of PSCs with high efficiency and good stability.

钙钛矿电池的稳定性，尤其是连续功率输出下的工作稳定性，是制约其商业化的瓶颈问题之一。而钙钛矿薄膜中的离子移动是造成其稳定性下降的其中一个重要因素。最近申请人采用原位交联的方法，在钙钛矿薄膜中引入可交联的有机添加剂，利用添加剂在晶界处的原位交联来阻塞离子沿晶界的迁移通道，抑制钙钛矿的离子移动，使器件的工作稳定性提升590倍，实现400小时的稳定连续功率输出。该工作表明可交联添加剂及原位交联方法是提高器件工作稳定性的有效手段。但是稳定性提升的内在机制、影响因素等还需深入研究。本项目旨在此基础上，发展新型可交联添加剂及相应器件工艺，实现>1000小时的工作稳定性。围绕此目标，针对可交联添加剂，探索器件在不同添加剂和制备工艺下效率和稳定性的变化规律。通过项目实施，将从添加剂化学结构、引入工艺、交联方式等多角度理解添加剂与器件效率和稳定性之间的内在联系，为高效稳定钙钛矿电池的制备提供新的思路与方法。

钙钛矿电池成本低，效率高，是当前最具应用潜力的新型光伏技术。目前钙钛矿电池效率已经突破25%，稳定性是制约钙钛矿电池商业化应用的关键核心问题之一。工作稳定性，即电池在光照、负载下的连续功率输出，最接近钙钛矿电池的真实发电应用环境，是衡量钙钛矿电池稳定性的关键指标。而光照负载下，由于钙钛矿内部离子迁移的加剧，往往造成其工作稳定性的显著下降。针对此，本项目围绕钙钛矿电池的工作稳定性，针对其内部离子迁移问题，通过自交联添加剂的引入来阻挡离子的主要迁移通道-晶界，抑制离子迁移；并结合添加剂结构设计以及交联方式的优化，同步提升电池效率和稳定性。此外，在电池设计上，通过界面交联、界面异质结强化以及电极防腐等措施，进一步抑制钙钛矿内离子迁移对电子传输层以及金属电极的影响，有效提升电池效率和稳定性。通过项目实施，在国际上刷新实现效率>24%的反向钙钛矿电池（Science 2022, 375, 434），创造当时反向钙钛矿电池效率的世界记录；同时器件表现出很好的工作稳定性，光照下连续功率输出1000小时，效率衰减<10%。相关工作突破了反向电池效率长期偏低的关键瓶颈问题；证明通过合理的器件设计，完全可以实现高效率的反向电池，极大地提振了人们对于钙钛矿电池，尤其是反向钙钛矿电池的研究信心。