无铅铁电偶极子光电转换器件的新材料探索及机理研究

Recently, the ferroelectric dipole materials based photo-to-elelctronic devices has been paid much attention due to the breakthorgh in efficiency. With the speedily growth of the sunlight to electricity conversion efficiency from 3% to 22.1% of perovskite -based solar cell, the long-term stability and Pb-free of this type of solar cells becomes serious issues, since they are the key factors to determine whether this solar cell would be commercialized. These issues are great challenge, however, we have to face these important key issues. Thus, in this proposal, 1) we present a fundamental study to develop new stable and Pb-free materials for ferroelectronic dipole solar cells, including materials design, devices fabrication. 2) We will fabricate several devices to study the mechanism of the solar cell. Furthermore, we will evaluate the structure of the materials how to affect the efficiency and stability of the devices, which is expected to improve the performance and stability of the devices. 3) The bandgap will be tuned by the dopant of B site of perovskites, we will study the optical properties of the materials. This research will have a great impact on the understanding of the performance of ferroelectronic dipole solar cells, and it would also have the potential to open a new way for developing new type of solar cells.

近年因铁电材料正将光电转化器件的效率推向理论极限，打破了传统太阳能电池的概念，同时有机无机复合钙钛矿型太阳能电池的光电转换效率从3％迅速飙升到22％，因此引起了极大的注目。但是要使其产业化应用，急需解决材料及器件的高效率化和稳定性及无铅化问题。这几个课题极富有挑战性，但又是急需解决的重大问题。本课题拟设计及构建高效稳定的新型无铅铁电偶极子光电器件和进行新材料探索。1）首先利用第一性原理和密度泛函理论计算，筛选出新型无铅铁电偶极子材料。研究材料的组成及结构对电子结构及光学性质影响。2）研究新型铁电材料结构和光电器件性能关系，阐明材料与器件性能构效关系，研究其光电转换机制。3）开发简易的合成方法并进行元素掺杂，调整带隙，实现微观调控，进而设计和构建具有高稳定性和高效率无铅环保型新型铁电太阳能电池。本项目的实施将开发出新型偶极子光电器件，为新材料探索和构建新型光电器件提供新思路。

近年，因铁电材料正将光电转化器件的效率推向理论极限，打破了传统太阳能电池的概念，同时有机无机复合钙钛矿型太阳能电池的光电转换效率从3.8％迅速飙升到25.7％，引起了极大的注目。但是要使其产业化应用，还需解决材料及器件的高效率化和稳定性及无铅化问题。本课题设计及制备了无铅铁电偶极子CsPbI2Br、Cs2PtI6等，研究了材料的组成、结构对光学性质影响，探索了新型铁电材料结构和光电器件性能关系，并阐明材料与器件性能构效关系，研究其光电转换机制。并通过开发新型方法、元素掺杂、界面工程等方式，调整铁电材料的带隙，实现微观调控，进而得到了具有高稳定性和高效率的新型铁电太阳能电池。. 同时，我们还研究了基于上述铁电材料的无空穴传输层光电器件，解决了基于铁电材料的无空穴传输层光电器件的界面电荷传输问题，课题组无空穴传输层器件效率已达到16.41%。探索了界面修饰对铁电材料光电器件的影响，界面钝化后，铁电材料的薄膜晶界明显减少，光致发光衰减时间的延长，钝化作用降低了薄膜的缺陷密度和晶界数量，有效地抑制了电荷复合，相较于基于基础器件，钝化后钙钛矿器件显示出更优异的光伏性能。作为铁电材料器件的一部分，我们开发了新型开发了非TiO2、SnO2的低温电子传输层材料，如SnS2、SnS2/SnS、Nb(OH)5及一体化电极等。为在低温下可制备柔性钙钛矿太阳能电池奠定一定的基础。