Huang Qianqian, Yin Wenxu, Gao Bo, Zeng Qingsen, Yao Dong, Zhang Hao, Zhao Yinghe, Zheng Weijia, Zhang Jiaqi, Yang Xuyong, Zhang Xiaoyu, Rogach Andrey L
Key Laboratory of Automobile Materials MOE, School of Materials Science & Engineering, and Jilin Provincial International Cooperation Key Laboratory of High-Efficiency Clean Energy Materials, Jilin University, Changchun, China.
State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun, China.
Light Sci Appl. 2024 May 11;13(1):111. doi: 10.1038/s41377-024-01441-1.
Quantum-confined CsPbBr perovskites are promising blue emitters for ultra-high-definition displays, but their soft lattice caused by highly ionic nature has a limited stability. Here, we endow CsPbBr nanoplatelets (NPLs) with atomic crystal-like structural rigidity through proper surface engineering, by using strongly bound N-dodecylbenzene sulfonic acid (DBSA). A stable, rigid crystal structure, as well as uniform, orderly-arranged surface of these NPLs is achieved by optimizing intermediate reaction stage, by switching from molecular clusters to mono-octahedra, while interaction with DBSA resulted in formation of a CsO monolayer shell capping the NPL surface. As a result, both structural and optical stability of the CsPbBr NPLs is enhanced by strong covalent bonding of DBSA, which inhibits undesired phase transitions and decomposition of the perovskite phase potentially caused by ligand desorption. Moreover, rather small amount of DBSA ligands at the NPL surface results in a short inter-NPL spacing in their closely-packed films, which facilitates efficient charge injection and transport. Blue photoluminescence of the produced CsPbBr NPLs is bright (nearly unity emission quantum yield) and peaks at 457 nm with an extremely narrow bandwidth of 3.7 nm at 80 K, while the bandwidth of the electroluminescence (peaked at 460 nm) also reaches a record-narrow value of 15 nm at room temperature. This value corresponds to the CIE coordinates of (0.141, 0.062), which meets Rec. 2020 standards for ultra-high-definition displays.
量子限域的CsPbBr钙钛矿是用于超高清显示器的有前景的蓝色发光体，但其由高离子性导致的软晶格稳定性有限。在此，我们通过使用强结合的N-十二烷基苯磺酸（DBSA）进行适当的表面工程，赋予CsPbBr纳米片（NPLs）类似原子晶体的结构刚性。通过优化中间反应阶段，从分子簇转变为单八面体，实现了这些NPLs稳定、刚性的晶体结构以及均匀、有序排列的表面，同时与DBSA的相互作用导致形成覆盖NPL表面CsO单层壳。结果，DBSA的强共价键增强了CsPbBr NPLs的结构和光学稳定性，抑制了可能由配体解吸引起的不期望的相变和钙钛矿相分解。此外，NPL表面相当少量的DBSA配体导致其紧密堆积薄膜中NPL间间距较短，这有利于高效电荷注入和传输。所制备的CsPbBr NPLs的蓝光光致发光明亮（发射量子产率接近1），在80 K时于457 nm处达到峰值，带宽极窄，为3.7 nm，而电致发光的带宽（在460 nm处达到峰值）在室温下也达到创纪录的窄值15 nm。该值对应于CIE坐标（0.141, 0.062），符合超高清显示器的Rec. 2020标准。
