Molecular Engineering Regulation Achieving Out‐of‐Plane Polarization in Rare‐Earth Hybrid Double Perovskites for Ferroelectrics and Circularly Polarized Luminescence

• Published in: Angewandte Chemie 2024-09, Vol.136 (39), p.n/a
• Main Authors: Wang, Na, Xu, Ze‐Jiang, Ni, Hao‐Fei, Luo, Wang, Li, Hua‐Kai, Ren, Mei‐Ling, Shi, Chao, Ye, Heng‐Yun, Fu, Xiao‐Bin, Zhang, Yi, Miao, Le‐Ping
• Format: Article
• Language: English
• Subjects: Cations; Circular polarization; circularly polarized luminescence; Coexistence; Crystal lattices; Curie temperature; Ferroelasticity; ferroelectric; Ferroelectric materials; Ferroelectricity; Ferroelectrics; Linear polarization; Luminescence; molecular engineering; Optoelectronic devices; out-of-plane polarization; Perovskites; Polarization; rare-earth hybrid double perovskites; Substitutes; Vertical polarization
• ISSN: 0044-8249; 1521-3757
• DOI: 10.1002/ange.202409796

Out‐of‐plane polarization is a highly desired property of two‐dimensional (2D) ferroelectrics for application in vertical sandwich‐type photoferroelectric devices, especially in ultrathin ferroelectronic devices. Nevertheless, despite great advances that have been made in recent years, out‐of‐plane polarization remains unrealized in the 2D hybrid double perovskite ferroelectric family. Here, from our previous work 2D hybrid double perovskite HQERN ((S3HQ)4EuRb(NO3)8, S3HQ=S‐3‐hydroxylquinuclidinium), we designed a molecular strategy of F‐substitution on organic component to successfully obtain FQERN ((S3FQ)4EuRb(NO3)8, S3FQ=S‐3‐fluoroquinuclidinium) showing circularly polarized luminescence (CPL) response. Remarkably, compared to the monopolar axis ferroelectric HQERN, FQERN not only shows multiferroicity with the coexistence of multipolar axis ferroelectricity and ferroelasticity but also realizes out‐of‐plane ferroelectric polarization and a dramatic enhancement of Curie temperature of 94 K. This is mainly due to the introduction of F‐substituted organic cations, which leads to a change in orientation and a reduction in crystal lattice void occupancy. Our study demonstrates that F‐substitution is an efficient strategy to realize and optimize ferroelectric functional characteristics, giving more possibility of 2D ferroelectric materials for applications in micro‐nano optoelectronic devices. F‐substitution achieves out‐of‐plane and multipolar axis multiferroicity and enhances the Tc 94 K in rare‐earth hybrid double perovskite ferroelectric with CPL response. It reveals that F‐substitution is a powerful approach to controlling the performances of ferroic materials and providing new prospects for applications in next‐generation ferroelectric micro‐nano devices.