工作状态下钙钛矿光伏电池功率输出性能与载流子动力学关系研究

The study on the correlation between the photoelectric conversion process and the photovoltaic performance of the device is significant for the deeper understanding about the structure-activity relationship, which is beneficial to further optimization of photovoltaic devices. Generally, the photoelectric conversion dynamics are investigated without power output, in which the tested devices are always confined to ‘open circuit’ or ‘short circuit’ conditions. However, these two simulated conditions cannot be used to give a comprehensive representation of the photoelectric conversion process in real working conditions (such as in various load and solar irradiation). In addition, short-time pulse laser is always adopted, of which the photon flux density is greatly larger than that of the natural light. The obtained knowledge of carrier dynamics based on pulse laser conditions might deviate from the real carrier dynamics of device under natural irradiation. In this proposal, a programmable continuous laser diode is adopted to simulate the solar irradiation and a digital sourcemeter is employed to modulate the device working conditions. The photovoltaic conversion dynamics of perovskite solar cell under various working conditions are investigated by combining the time-resolved photoelectric and spectrum techniques from a multi-time and multi-spatial scale. The corresponding relation between material compositions, morphologies, structures and the energy state distribution will be built. The inner correlation between the initial charge generation, charge carrier diffusion/migration, charge carrier transport/recombination and the power output performance of the perovskite solar cell under real working conditions will be revealed. Finally, the crucial dynamic determinant that limits the power output performance will be given.

研究钙钛矿太阳能电池的性能与其光电转换过程之间的关系有助于深入认识该类光伏器件的构效关系，从而进一步提高其光伏性能。迄今对光电转换动力学过程的研究工作普遍针对器件的“开路”或“短路”对外输出功率为零的状态。然而，这两种模拟工作条件下的载流子动力学规律并不能完全反映器件在真实工作状态下(负载、光照等)的情况。此外，相关研究大多采用短脉冲激光为光源，其光子数密度远大于太阳光照条件，对认知真实工作状态下的载流子动力学带来了偏差。本项目拟开展模拟自然光照度下和外加电路负载的钙钛矿光伏器件的光电转换过程研究。利用可调制连续光源模拟太阳光辐照，结合偏置电压模拟器件的真实工作状态，通过时间分辨光电/光谱技术，从多时间尺度、多空间层面上研究材料和器件结构与能态分布关系，以及真实工作状态下载流子输运/复合过程对器件输出功率的影响规律，揭示影响器件发挥其光伏性能的关键结构和动力学因素。

在十四五开局年之际，面向我国“双碳”发展目标，钙钛矿光伏嫣然成为光电转换研究卓尔不群的领域。光伏器件性能节节攀升，但真实器件工作状态下的载流子动力学规律研究亟待突破。本项目从钙钛矿光伏电池器件结构与电子结构关联性入手，发展工作状态下载流子动力学研究新手段，旨在阐明模拟工作状态下器件内载流子动力学的基本规律。主要包括：1）混合阳离子修饰、形貌控制、晶界缺陷钝化以及添加剂工程等对本征薄膜中缺陷态性质调控作用；2）表界面修饰对光生载流子动力学影响机制；3)工作器件迁移离子和载流子动力学作用关系。同时，还培育了原位-实时钙钛矿薄膜结晶动力学表征技术以及钙钛矿薄膜上转换发光特性研究。上述成果从多时间尺度多空间维度探究钙钛矿光伏真实器件条件下光生载流子动力学，对理解工作状态下的载流子动力学具有重要参考价值。