钙钛矿太阳能电池中界面调控及界面载流子动力学过程研究

Perovskite solar cells have attracted considerable attention due to the advantages of low-cost fabrication and high power conversion efficiency up to 20.1%. It is worth noting that the performance and lifetime are not only critically depend on the properties of the perovskite layers but also the interfaces in the cells. In particular, the interfaces between perovskite layers and the electron transport layers have a significant influence on the charge transfer processes, because the charge recombination usually occurs at interfacial defects. In order to further enhance device performance, the modification of interface is often applied to alter the interface properties, including establishment of ohmic contacts, adjustment of interface energy-level alignment and regulation of carrier recombination dynamics and so on. However, the microscopic mechanism of these modifications has not been fully understood by the moment, so further studies are needed. In this project, we will focuses on investigating the interfacial modification between perovskite layer and TiO2 electron transport layer. The fullerene derivatives self-assembled monolayers are used to optimize interfacial properties of the TiO2 layer. The charge carrier decay dynamics are studied by transient photovoltage in a working device and the interfacial electron structures are further investigated by the surface-sensitive analytical techniques based on synchrotron radiation. Through the analysis of the correlation between carrier recombination dynamics, interfacial energy level and device performance, the microscopic mechanism will reveal the route to choose the proper interfacial modification material for the TiO2 layer, which will facilitate the reasonably well design for low-cost and high-efficiency perovskite solar cells.

钙钛矿太阳能电池的能量转换效率已经达到了20.1%，而且可以通过低成本溶液加工方式制备，因此成为太阳能电池研究领域的热点。其中电子传输层的界面性质对载流子动力学过程有着显著的影响，其界面性质的调控对于进一步提升钙钛矿太阳能电池的能量转换效率至关重要。本项目针对钙钛矿太阳能电池中的钙钛矿/TiO2电子传输层的界面调控展开研究，采用富勒烯衍生物自组装单分子层对TiO2薄膜进行界面修饰，利用瞬态光伏技术和结合基于同步辐射的多种表面分析技术，在微观尺度上深入研究钙钛矿太阳能电池中的界面载流子复合动力学过程以及界面电子结构。拟通过分析界面调控对器件性能的影响机制，阐明钙钛矿太阳能电池中TiO2电子传输层界面修饰材料的选择依据，为开发低成本、高效率钙钛矿太阳能电池提供理论支撑和技术指导。

太阳能电池可以将太阳能转换为电能，这对于解决当前的能源危机和环境污染等问题有着重要的意义。其中有机太阳能电池具有制备工艺简单、质量轻、成本低、易制成大面积柔性器件等优势，但是效率和稳定性还不理想；钙钛矿太阳能电池的具有较高的能量转换效率，但是稳定性问题限制了实际应用；硒硫化锑太阳能电池具有优异的稳定性，但是器件效率还需要进一步提高。通过界面调控来提器件的能量转化效率和稳定性是目前的研究热点。本研究利用基于同步辐射的多种表面分析技术并结合瞬态光伏技术，对太阳能电池中的界面相互作用以及界面调控展开研究，包括有机太阳能电池、钙钛矿太阳能电池以及硒硫化锑太阳能电池，获得了界面处所发生的物理化学过程、电子结构信息以及载流子复合过程等重要数据。研究结果有助于理解器件界面结构与性能之间的内在联系，从而为研究和开发高效、稳定的太阳能电池提供理论依据和技术指导。项目资助发表学术论文12篇，协助培养硕士研究生2名。项目批准经费21.0000万元，累计支出15.8577万元，结余经费5.1423万元，将继续用于项目的后续科学研究与发展。