Wang Guoliang, Ren Bainian, Mei Xinyi, Zhang Mingxu, Qiu Junming, Sun Zhimei, Zhang Xiaoliang
School of Materials Science and Engineering, Beihang University, Beijing, 100191, China.
Adv Mater. 2025 Sep;37(35):e2508425. doi: 10.1002/adma.202508425. Epub 2025 Jun 19.
Cesium-formamidinium lead triiodide perovskite quantum dots (CsFAPbI PQDs) receive increasing attention for new-generation solar cells due to their outstanding optoelectronic properties and solution processibility. However, during the synthesis of CsFAPbI PQDs, PQDs seriously suffer from the ligand detachment from the PQD surface under the polar antisolvent, leaving numerous surface vacancies that significantly compromise the surface lattice integrity and optoelectronic properties of PQDs. A facile dual-ionic charge compensation strategy is introduced through the bimolecular nucleophilic substitution (S2) to reinforce the surface lattice of CsFAPbI PQDs. The dual-ionic ligands produced during the S2 reaction could in situ fill the surface vacancies of PQDs in the nonpolar solvent, which significantly improves the surface lattice integrity and thus the optoelectronic properties of PQDs, substantially diminishing trap-assisted nonradiative recombination. Consequently, the PQDs solar cells show a power conversion efficiency of up to 18.17%, representing the highest efficiency in CsFAPbI PQD solar cells. The remarkable photovoltaic performance is attributed to the reinforced surface lattice of PQDs, suppressing the energy losses induced by the nonradiative recombination. This study provides crucial design principles for optimizing the crystalline structure integrity of PQDs, which also paves a new avenue for developing high-performance solar cells or other optoelectronic devices.
铯-甲脒铅三碘化物钙钛矿量子点（CsFAPbI量子点）因其优异的光电性能和溶液可加工性，在新一代太阳能电池领域受到越来越多的关注。然而，在CsFAPbI量子点的合成过程中，量子点在极性反溶剂作用下严重遭受配体从量子点表面脱离的问题，留下大量表面空位，这显著损害了量子点的表面晶格完整性和光电性能。通过双分子亲核取代反应（S2）引入了一种简便的双离子电荷补偿策略，以强化CsFAPbI量子点的表面晶格。S2反应过程中产生的双离子配体能够在非极性溶剂中原位填充量子点的表面空位，这显著提高了表面晶格完整性，进而提升了量子点的光电性能，大幅减少了陷阱辅助非辐射复合。因此，量子点太阳能电池展现出高达18.17%的功率转换效率，代表了CsFAPbI量子点太阳能电池的最高效率。卓越的光伏性能归因于量子点强化的表面晶格，抑制了非辐射复合引起的能量损失。本研究为优化量子点的晶体结构完整性提供了关键的设计原则，也为开发高性能太阳能电池或其他光电器件开辟了一条新途径。
