Wang Yao, Yuan Jianyu, Zhang Xuliang, Ling Xufeng, Larson Bryon W, Zhao Qian, Yang Yingguo, Shi Yao, Luther Joseph M, Ma Wanli
Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Joint International Research Laboratory of Carbon-Based Functional Materials and Devices, Soochow University, 199 Ren-Ai Road, Suzhou Industrial Park, Suzhou, 215123, P. R. China.
Chemistry and Nanoscience Department, National Renewable Energy Laboratory, Golden, CO, 80401, USA.
Adv Mater. 2020 Aug;32(32):e2000449. doi: 10.1002/adma.202000449. Epub 2020 Jul 1.
Lead-halide perovskite quantum dots (PQDs) or more broadly, nanocrystals possess advantageous features for solution-processed photovoltaic devices. The nanocrystal surface ligands play a crucial role in the transport of photogenerated carriers and ultimately affect the overall performance of PQD solar cells. Significantly improved CsPbI PQD synthetic yield and solar-cell performance through surface ligand management are demonstrated. The treatment of a secondary amine, di-n-propylamine (DPA), provides a mild and efficient approach to control the surface ligand density of PQDs, which has an apparently different working mechanism compared to previously reported surface treatments. Using an optimal DPA concentration, the treatment can simultaneously remove both long-chain insulating surface ligands of oleic acid and oleylamine, even for unpurified PQDs with high ligand density. As a result, the electrical coupling between PQDs is enhanced, leading to improved charge transport, reduced carrier recombination, and a high power conversion efficiency approaching 15% for CsPbI -PQD-based solar cells. In addition, the production yield of CsPbI PQDs can be increased by a factor of 8. These results highlight the importance of developing new ligand-management strategies, specifically for emerging PQDs to achieve scalable and high-performance perovskite-based optoelectronic devices.
铅卤化物钙钛矿量子点（PQDs），或者更广义地说，纳米晶体，对于溶液处理的光伏器件具有有利特性。纳米晶体表面配体在光生载流子的传输中起着关键作用，并最终影响PQD太阳能电池的整体性能。通过表面配体管理，CsPbI PQD的合成产率和太阳能电池性能得到了显著提高。仲胺二正丙胺（DPA）的处理提供了一种温和且有效的方法来控制PQD的表面配体密度，与先前报道的表面处理相比，其工作机制明显不同。使用最佳的DPA浓度，该处理甚至可以同时去除油酸和油胺等长链绝缘表面配体，即使是对于具有高配体密度的未纯化PQD也是如此。结果，PQD之间的电耦合增强，导致电荷传输改善、载流子复合减少，基于CsPbI -PQD的太阳能电池的功率转换效率接近15%。此外，CsPbI PQDs的产率可以提高8倍。这些结果突出了开发新的配体管理策略的重要性，特别是对于新兴的PQD，以实现可扩展的高性能钙钛矿基光电器件。
