近日，吉林大学的张晓宇及其研究小组与香港城市大学的Andrey L. Rogach以及加拿大维多利亚大学的Weijia Zheng等人合作并取得一项新进展。经过不懈努力，他们通过增强CsPbBr₃纳米薄片的晶体完整性和结构刚性实现窄色饱和蓝色发射。相关研究成果已于2024年5月11日在国际知名学术期刊《光：科学与应用》上发表。

该研究团队通过适当的表面工程，借助强结合的n-十二烷基苯磺酸(DBSA)赋予CsPbBr₃纳米薄片(NPLs)以原子晶体般的结构刚性。通过优化中间反应阶段，从分子簇切换到单八面体，从而获得稳定、刚性的晶体结构以及均匀、有序的表面，而与DBSA的相互作用导致Cs_xO单层壳覆盖在NPL表面。因此，DBSA的强共价键增强了CsPbBr₃ NPLs的结构和光学稳定性，抑制了配体脱附可能引起的钙钛矿相的不利相变和分解。

此外，NPL表面DBSA配体数量稀少，使得紧密堆叠的薄膜中NPL间间距极短，极大地促进了电荷的有效注入和传输。制备出的CsPbBr₃ NPLs在蓝色光致发光方面表现出色，其发光亮度接近1的发射量子产率，在80K时峰值波长达到457nm，且带宽极窄，仅为3.7nm。即使在室温下，其电致发光带宽（峰值460nm）也达到了创纪录的15nm窄值。这一性能对应的CIE坐标为(0.141,0.062)，完全符合超高清显示器的Rec. 2020标准。

据悉，量子受限的CsPbBr₃钙钛矿是超高清显示器中很有前途的蓝色发射器，但其高离子性质造成的软晶格具有有限的稳定性。

附：英文原文

Title: Enhancing crystal integrity and structural rigidity of CsPbBr₃ nanoplatelets to achieve a narrow color-saturated blue emission

Author: 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.

Issue&Volume: 2024-05-11

Abstract: Quantum-confined CsPbBr₃ 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 CsPbBr₃ 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 Cs_xO monolayer shell capping the NPL surface. As a result, both structural and optical stability of the CsPbBr₃ 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 CsPbBr₃ NPLs is bright (nearly unity emission quantum yield) and peaks at 457nm with an extremely narrow bandwidth of 3.7nm at 80K, while the bandwidth of the electroluminescence (peaked at 460nm) also reaches a record-narrow value of 15nm 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.

DOI: 10.1038/s41377-024-01441-1

Source: https://www.nature.com/articles/s41377-024-01441-1