Mizoguchi Shoki, Sumikoshi Shunsuke, Abe Haruka, Ito Yuta, Yamakado Ryohei, Chiba Takayuki
Graduate School of Organic Materials Science, Yamagata University, 4-3-16 Jonan, Yonezawa, Yamagata 992-8510, Japan.
ACS Omega. 2024 Aug 1;9(32):34692-34699. doi: 10.1021/acsomega.4c03488. eCollection 2024 Aug 13.
Perovskite nanocrystals (NCs) with long alkyl ligands cannot easily form high-quality composite films owing to their poor dispersibility in π-conjugated small molecules and polymer host materials. In this study, we demonstrated that the aromatic ligand exchange of mixed-cation FACsPbBr NCs using 2,2-diphenylethylamine (DPEA) can not only enable the fabrication of high-efficiency light-emitting diodes (LEDs) but also allows dispersibility in host materials. The DPEA-NC film exhibited a pure green wavelength of 530 nm and a full width at half-maximum of 20.9 nm with a photoluminescence quantum yield of 90.9%. A DPEA-NC LED achieved a luminance of 39,700 cd/m and an external quantum efficiency of 18.6% even in a thick NC film. Interestingly, the DPEA-NCs formed a composite film with small-molecule tris(4-carbazoyl-9-ylphenyl)amine. The operational stability of this composite LED was eight times higher than that of the DPEA-NC LED owing to enhanced hole-electron charge balance and the suppression of perovskite NC degradation. Therefore, the aromatic DPEA ligand exchange of perovskite NCs is an effective way to improve their electrical properties and operational device stabilities.
具有长烷基配体的钙钛矿纳米晶体（NCs）由于其在π共轭小分子和聚合物主体材料中的分散性差，难以轻易形成高质量的复合薄膜。在本研究中，我们证明了使用2,2-二苯乙胺（DPEA）对混合阳离子FACsPbBr NCs进行芳香配体交换，不仅能够制造高效发光二极管（LED），还能使其在主体材料中具有分散性。DPEA-NC薄膜呈现出530 nm的纯绿色波长，半高宽为20.9 nm，光致发光量子产率为90.9%。即使在较厚的NC薄膜中，DPEA-NC LED仍实现了39700 cd/m的亮度和18.6%的外量子效率。有趣的是，DPEA-NCs与小分子三（4-咔唑-9-基苯基）胺形成了复合薄膜。由于增强了空穴-电子电荷平衡并抑制了钙钛矿NC的降解，这种复合LED的工作稳定性比DPEA-NC LED高八倍。因此，钙钛矿NCs的芳香DPEA配体交换是改善其电学性质和器件工作稳定性的有效方法。
