Zhao Chenjing, Zhu Chunrong, Yu Yue, Xue Wenhao, Liu Xiaoyun, Yuan Fang, Dai Jinfei, Wang Shuangpeng, Jiao Bo, Wu Zhaoxin
Key Laboratory for Physical Electronics and Devices of the Ministry of Education & Shaanxi Key Lab of Information Photonic Technique, School of Electronic Science and Engineering, Xi'an Jiaotong University, Xi'an, Shaanxi 710049, China.
School of Optoelectronic Engineering, Xidian University, Xi'an 710071, Shaanxi China.
ACS Appl Mater Interfaces. 2023 Aug 23;15(33):40080-40087. doi: 10.1021/acsami.3c08008. Epub 2023 Aug 14.
Lead halide perovskite quantum dots (QDs) have attracted great interest for application in light-emitting diodes (LEDs) due to their high photoluminescence quantum yield (PLQY), solution processability, and high color purity, showing great potential for next-generation full-color display and lighting technologies. Conventional long-chain insulating oleic acid (OA)/oleamine (OAm) ligands exhibit dynamic binding to the surface of QDs, resulting in a plethora of extra surface defects and inferior optoelectronic properties. Herein, a sole multifunctional ligand with optimized carbon chain length, that is, 2-thiophenepropylamine bromide (ThPABr), was creatively designed and introduced into CsPbBr QDs, which not only replaces OAm and provides a bromine source but also coordinates with the uncoordinated surface Pb of QDs through the thiophene, passivating surface defects and increasing the PLQY of the film to 83%. More importantly, the interaction between the electron donor-thiophene ring and QDs can enhance electron injection and improve carrier balance. The resulting green LED exhibited significant performance improvement, showing ultrahigh spectral stability under high operating voltage, achieving a maximum external quantum efficiency of 10.5%, and extending the operating lifetime to 5-fold that of the reference. Designing a single multifunctional ligand presents a promising and convenient strategy for selecting surface ligands that can enhance the performance of LEDs or other optoelectronic devices.
卤化铅钙钛矿量子点（QDs）因其高光致发光量子产率（PLQY）、溶液可加工性和高色纯度，在发光二极管（LED）应用中引起了极大关注，显示出在下一代全彩显示和照明技术方面的巨大潜力。传统的长链绝缘油酸（OA）/油胺（OAm）配体与量子点表面表现出动态结合，导致大量额外的表面缺陷和较差的光电性能。在此，创造性地设计并将一种具有优化碳链长度的单一多功能配体，即2-噻吩丙胺溴化物（ThPABr）引入到CsPbBr量子点中，它不仅取代了OAm并提供溴源，还通过噻吩与量子点未配位的表面Pb配位，钝化表面缺陷并将薄膜的PLQY提高到83%。更重要的是，电子供体噻吩环与量子点之间的相互作用可以增强电子注入并改善载流子平衡。由此得到的绿色LED表现出显著的性能提升，在高工作电压下显示出超高的光谱稳定性，实现了10.5%的最大外量子效率，并将工作寿命延长至参考值的5倍。设计单一多功能配体为选择可提高LED或其他光电器件性能的表面配体提供了一种有前景且便捷的策略。
