锡基钙钛矿薄膜的结晶行为与缺陷调控机理研究

Organic-inorganic metal halide perovskites solar cells have recently attracted tremendous attention due to their impressive efficiency increase witnessed in the past few years, as well as the low-cost and abundant raw materials, great tunability in the component. The organic-inorganic hybrid nature of perovskite materials promises both the superior carrier mobility of inorganic semiconductors and the processability of organic materials. To date, mainstream perovskite solar cells development has focused on methylammonium lead iodide and formamidinium lead iodides. However, the large-scale use of soluble lead-based materials raises concern about their potential toxicity and environmental effect, thus calling for the development of nontoxic replacement of lead perovskite without affecting severely their photovoltaic performance. Developing the lead-free perovskite would also expanding the pervovskite optical band absorption and the inherent electronic transport properties, aiming to harvest the entire visible region solar spectrum as well as efficiently separate and collect the photon generated carriers. Here in this project, we will focus on the fundamental issues of tin perovskites’ application in the energy conversion, such as the development of new material composition and tin perovskite film deposition methods, the crystallization process and the origins of the defects in the perovskite films. The relationship between the tin perovskite composition-film structure-mechanism will also been systematically investigated with a purpose to better bridging this promising material to application. This would greatly promote the developing of new high efficient and environment friendly perovskite photovoltaic devices, and also the fundamental understanding of the perovskite film crystallization through the molecular scale. The contribution of this project would benefit the broadening the application and of this class of lead-free perovskite thin films in environmental and energy conversion field.

钙钛矿太阳能电池因其原材料丰富、成分可调、工艺简单、光电转换效率高等优点，成为近年来光伏领域的重要发展方向之一.目前，该类太阳能电池中常用的吸光材料多为铅基钙钛矿材料，如甲胺基碘化铅、甲脒基碘化铅等。然而大规模使用此类水溶性铅盐引起了环保与健康方面的潜在担忧。因此开发性能稳定的非铅钙钛矿光伏材料，既可以有效解决现有材料中可溶性铅含量对产业化应用中产生的环境影响，同时可以进一步拓宽该类半导体材料的光学性能和调控其电荷传输特性，从而提高其对可见光的有效利用。本项目将结以锡基钙钛矿薄膜材料在能源转换与利用领域的应用为工作重心，积极开发新材料的合成与制备方法，构筑新型光伏材料体系，探索薄膜生长规律，系统研究新材料/新结构/新机理的内在关联，搭建材料与应用的桥梁，努力实现从分子水平层面构建新型钙钛矿多功能薄膜材料的基础研究，并拓宽该类材料在环境与能源领域中的应用研发。

目前，钙钛矿太阳能电池中常用的吸光材料多为铅基钙钛矿材料，如甲胺铅碘、甲脒铅碘、铯铅碘等，然而大规模使用此类含铅化合物引发了广泛的环保与健康担忧。因此开发性能稳定的非铅钙钛矿光伏材料与器件势在必行。因此本项目围绕非铅钙钛矿薄膜的结晶过程与缺陷调控这一核心研究内容，从锡基钙钛矿材料的结晶行为与调控、钙钛矿薄膜的缺陷调控与形成机理、钙钛矿太阳能电池器件的界面修饰与能级调控三个研究方面开展了系列研究工作，积极开发锡基钙钛矿的可控合成与制备方法，分离了影响钙钛矿薄膜结晶行为的关键中间体，并研究其晶体结构特性，建立中间体与最终钙钛矿薄膜晶型转换之间的联系，并研究关键中间体的可控制备技术，进一步通过系统调控钙钛矿的制备条件（如反应前驱体的化学计量比、制备过程中的气氛环境等因素），实现了对钙钛矿薄膜缺陷浓度的调控并建立相应的影响规律，结合锡基钙钛矿薄膜的缺陷浓度形成规律与机制，开发了一系列用于缺陷钝化的高效小分子钝化材料，并开展了钙钛矿薄膜与电荷传输层之间的电荷跃迁与传输规律研究，并表征相应的光生电子与空穴的有效扩散系数与扩算长度，建立起钙钛矿薄膜界面的电荷传输与复合机制，系统研究新材料/新结构/新机理的内在关联，搭建起了非铅钙钛矿材料与光电应用的桥梁。本项目的实施对深入理解非铅钙钛矿薄膜的成膜机制与缺陷调控机理具有重要意义，将为此类非铅钙钛矿光电器件的应用与发展提供必要技术支撑与保障。..在项目资助期间，项目研究成果共发表SCI论文23篇（其中JCR一区论文20篇，影响因子大于10论文11篇，1篇论文入选JMCC 2019年度热点论，所发表论文目前SCI引用次数已达300余次，单篇引用最高已达71次（Google Scholar数据），撰写英文专著2章节（其中1章节已出版），申请中国发明专利1项，项目研究成果应邀在国内外学术会议上作邀请报告10余次。