功能化小分子调控反溶剂工程提升钙钛矿太阳能电池效率与稳定性

Functionalized Small Molecules Regulated Anti-Solvent Engineering Enabling Efficient and Stable Perovskite Solar Cells

摘要:

在全球能源危机背景下，钙钛矿太阳能电池（Perovskite solar cells，PSCs）凭借高光电转换效率和低成本优势，成为新一代光伏电池的有力竞争者。PSCs经过十余年的快速发展，其光电转化效率已提升至26.1%，展现出广阔的应用前景。然而，钙钛矿材料固有的缺陷态和环境敏感性，严重制约了器件的长期稳定性，阻碍了商业化进程。为此，通过反溶剂工程引入功能化小分子5'-碘代-3'-辛基-[2,2'-联噻吩]-5-甲醛（IN1712），以调整钙钛矿太阳能电池的缺陷态及提升器件的稳定性。研究表明，IN1712中的羰基和噻吩基团可与钙钛矿薄膜表面未配位的Pb²⁺离子相互作用，实现有效钝化，减少钙钛矿薄膜中缺陷态的密度及非辐射复合，优化电荷传输性能。同时，通过反溶剂工程引入的IN1712有效抑制了钙钛矿薄膜表面PbI₂相的生成，改善了钙钛矿的结晶效果，进一步减少了钙钛矿薄膜中缺陷位点。得益于上述优化，修饰后的器件表现出显著的光电性能，其开路电压从1.10 V提高到1.16 V，填充因子从80.39%提高到83.54%，冠军器件的光电转化效率从21.86%提高到24.09%。更重要的是，IN1712的修饰显著提高了电池器件的湿度稳定性，相较于未修饰器件在相对湿度60%±5%的条件下老化400 h后效率降至60.1%，修饰器件在相同条件下老化800 h仍保持80.1%的初始效率。通过功能化小分子调控反溶剂工程，为实现高效稳定钙钛矿太阳能电池的发展提供了新的策略和理论指导。

Abstract:

Amid the 21st-century global energy crisis， perovskite solar cells （PSCs） have emerged as a promising photovoltaic technology， achieving rapid advancements over the past decade. With a record-high photoelectric conversion efficiency of 26.1%， PSCs demonstrate great potential for commercial application. However， the intrinsic defects in perovskite materials makes it difficult to achieve long-term operational stability of its devices， which becomes an important obstacle on the road to commercialization. In this study， a 5'-iodo-3'-octyl-［2，2'-bithiophene］-5-formaldehyde （IN1712） functionalized small molecule additive is introduced via anti-solvent engineering to mitigate the defect states and enhance device stability. It is found that the carbonyl and thiophene in IN1712 effectively passivate uncoordinated Pb²⁺ ions on the surface of perovskites， suppressing defect formation， reducing non-radiative recombination， and improving charge-transfer efficiency at the interfaces. Additionally， IN1712 introduced by anti-solvent engineering significantly inhibit the formation of PbI₂， enhances perovskite crystallization， and further reduce the defect sites in perovskite films. As a result， the modified PSCs exhibit notable performance improvements， with the open circuit voltage increasing from 1.10 to 1.16 V， the fill factor rising from 80.39% to 83.54%， and the photoelectric conversion efficiency of the champion device boosts from 21.86% to 24.09%. More importantly， the IN1712 treatment significantly enhances the humidity stability of the devices， with unencapsulated devices retaining 80.1% of their initial efficiency after 800 h at 60%±5% relative humidity， compared to only 60.1% for control devices after 400 h. This work provides valuable insights for the development of high-efficiency and stable perovskite solar cells.