Discovery of One-Dimensional Rare-Earth Hybrid Nitrate Double Perovskites

Abstract

Rare-earth hybrid nitrate double perovskites (REHNDPs) have recently emerged as an intriguing subclass of functional materials, combining structural diversity with rich intrinsic optoelectronic, magnetic, piezoelectric, and ferroelectric properties. Although notable progress has been made in three-dimensional (3D) and 2D REHNDPs, 1D counterparts have yet to be discovered. Herein, by introducing the bulky organic cation 1-adamantyltrimethylammonium (TMAA+), we report a family of 1D REHNDPs with the general formula (TMAA)2LnCs(NO3)6 (Ln = La3+, Ce3+, Pr3+, Nd3+, Sm3+, and Eu3+). Distinct from the μ2-κ3(O,O′,O″) mode characteristic of 2D and 3D REHNDPs, the bridging NO3− ligands adopt a μ2-κ3(O,O′) coordination mode in 1D counterparts. Strikingly, (TMAA)2SmCs(NO3)6 possesses a step-like high-temperature dielectric switch at 431.7 K. (TMAA)2EuCs(NO3)6 shows brilliant photoluminescence with a quantum yield of 65.46% and a lifetime of 5.21 ms. The X-ray detector based on (TMAA)2EuCs(NO3)6 demonstrates high X-ray sensitivity of 560 μC Gyair−1 cm−2 and a low detection limit of 153 nGyair s−1 under a bias of 25 V. This work bridges a critical dimensional gap and significantly expands the structural and functional portfolio of the REHNDPs.