高效稳定锡基钙钛矿太阳能电池

有机-无机铅卤钙钛矿太阳能电池光电转化效率9年之内从3%左右增长到23.7%（2018年认证效率），成为国际研究的焦点。然而，重金属铅的使用限制了其产业化应用。如何开发环境友好非铅钙钛矿光伏器件成为国内外能源领域新的机遇与挑战。从结构上讲，Sn具有惰性ns2外层电子结构，因而Sn基钙钛矿是替代Pb基钙钛矿的首选。然而，Sn基钙钛矿中Sn空位缺陷以及Sn2+的易氧化特性严重影响了Sn基钙钛矿的稳定性，也成为其进一步提高效率的瓶颈。.本项目以实现高质量低缺陷Sn基钙钛矿多晶薄膜为核心，首先，从理论上揭示Sn钙钛矿缺陷形成与其调控的理论机制；其次，从高纯亚锡原料入手，发展高纯亚锡原料的提纯新方法，以及发展新型稳定锡基钙钛矿新结构，从源头和根本上降低和抑制其缺陷态形成；最后，通过引入新型准二维锡基钙钛矿以及界面能级匹配工程钝化表面缺陷以及光伏器件开压损耗。最终实现高效稳定非铅钙钛矿电池。

The power conversion efficiency (PCE) of the solar cells based on organic-inorganic lead (Pb) halide perovskite material (perovskite solar cells, PSCs) has dramatically increased from 3% up to 23.7% (certificated in 2018) within 9 years. However, the use of the heavy metal, Pb, limited the commercial application of PSCs. Therefore, it becomes the opportunity as well as challenge for the researchers all over the world to develop eco-friendly Pb-free perovskite photovoltaic devices. From the viewpoint of crystal structure, tin (Sn) based perovskite material possesses two inert electrons at ns2 orbital that is similar to Pb, which makes Sn-based perovskite the priority of Pb substitution. However, the presence of Sn vacancy defect and the easy oxidation of Sn2+ have a strong impact on the stability of Sn perovskite, which is the main bottleneck for further PCEs improvement. .In this project, we aim at the Sn-based perovskite polycrystalline films with low defect density and high quality. Firstly, the formation of defects in Sn-based perovskite and their regulation mechanism will be investigated theoretically. Then, from the viewpoint of raw materials, we will develop advanced purification methods for high purity Sn2+ as well as novel Sn-based perovskite structure with superior stability, which will fundamentally reduce and inhibit the formation of defect. And then, the quasi-two-dimensional Sn-based perovskite and interfacial engineering for energy level matching will be introduced to passivate surface defects and suppress the open voltage losses of photovoltaic devices. Finally, efficient and stable Pb-free PSCs could be realized.