活性层结构对钙钛矿光伏器件慢速动力学机理的影响研究

Perovskite solar cells have excellent performance, which is the focus of current research in the field of new energy. However, this kind of photovoltaic devices exhibit slow dynamic phenomena in the order of second or even minute, which makes it difficult to understand the photovoltaic conversion dynamics correctly. Up to now, the understanding of slow dynamics is still in the guessing stage, and there is no systematic understanding. Moreover, the complete solution of slow dynamics can not be obtained only through the study of transient photoelectric conversion dynamics under open or short circuit conditions. In this project, the normal structures of perovskite photovoltaic devices are taken as the research object, and the perovskite active layer is taken as the breakthrough point to establish the intrinsic relationship between perovskite chemical composition-structure-slow kinetics. For this purpose, the project comprehensively uses the means of composition control, structure characterization and transient research methods to study the correlation between chemical composition of perovskite active layer and its structure and trap-states. Transient optoelectronic technology combined with bias voltage is used to make the perovskite device in different working conditions, and the transport and recombination mechanism of slow components under different working conditions is explored. The time-resolved charge extraction technique was used to explore the mechanism of the effect of trap-states on slow dynamics. The mechanism of the effect of trap-states on slow kinetics was investigated. Through the above research, the mechanism of the effect of perovskite active layer structure on slow dynamics is revealed, which provides a new idea for understanding the photoelectric conversion mechanism of perovskite photovoltaic devices.

钙钛矿光伏器件性能优异，是当前新能源领域研究焦点。但该类光伏器件呈现出秒量级甚至分钟量级的慢速动力学现象，对正确认识光电转换动力学造成较大的困扰。迄今对慢速动力学的认识仍处于猜测阶段，尚缺乏系统认识，而且单纯通过开路或短路条件下的瞬态光电转换动力学研究无法获得慢速动力学过程的完整答案。本项目拟以正置结构的钙钛矿光伏器件为研究对象，以钙钛矿活性层为切入点，建立化学组成-结构-慢速动力学之间的内在联系。为此，本项目综合运用组分调控，结构表征和瞬态研究手段，研究钙钛矿活性层化学组成与结构和缺陷态属性的内在联系；运用瞬态光电技术，结合偏置电压使钙钛矿器件处于不同的工作状态，探究不同工作状态下慢成分传输与复合机制；运用时间分辨电荷抽取技术，探究缺陷态属性对慢速动力学的影响机制。通过上述研究，揭示钙钛矿活性层结构对慢速动力学的影响机理，为认识钙钛矿光伏器件光电转换机制提供新思路。

钙钛矿太阳能电池性能优异，是当前新能源领域研究焦点。但该类光伏器件呈现出秒量级甚至分钟量级的慢速动力学现象，对正确认识光电转换动力学造成较大的困扰。本项目以钙钛矿活性层为切入点，从化学组成和结构两个层面，探究不同工作状态下钙钛矿光伏器件中慢速动力学的演化规律，揭示钙钛矿活性层结构对慢速动力学的影响机理，建立化学组成-结构-慢速动力学内在的联系。主要包括：（1）混合阳（阴）离子、活性剂调控、界面修饰等对本征钙钛矿薄膜化学组成及结构进行调控；（2）探究活性层化学组成与结构和缺陷态属性的相关性，及其对本征光生载流子动力学影响机制；（3）不同工作状态下钙钛矿器件多时间尺度动力学过程，揭示了光生载流子动力学、离子迁移及慢速动力学相互影响对钙钛矿光伏器件性能及光电转换过程的影响机制。上述成果全新认识钙钛矿光伏器件多时间尺度动力学过程，对认识钙钛矿光伏器件光电转换机制具有重要科学意义，对器件材料、结构和工艺设计的优化具有重要参考价值。