Chiral Rare-Earth (Ce, Eu) Metal Halides with Bright Circularly Polarized Luminescence
Congcong Chen, Jian Chen, Zhongwei Chen, Huan Liu, Zixuan Zhang, Rui Chen, Haipeng Lu, Lingling Mao
Abstract
Chiral metal halide materials are emerging chiroptical materials that are easy to synthesize and have a wide tunability. Rare-earth (RE) metals are desirable components to be incorporated in the hybrid regime; however, they are typically difficult to handle for solution-based halide chemistry. Here, we report two new examples of chiral RE metal halides with Ce(III) and Eu(III) with chiral alkanolammonium cations ( R / S -3-hydroxyquinuclidium). These compounds crystallize in the non-centrosymmetric space group R 3, where their mirror-like symmetric circular dichroism (CD) and circularly polarized luminescence (CPL) further witness the chiral nature. The superior emission properties, including the high photoluminescence quantum yield of the Ce-based materials (84–90%) and Eu-based materials (27–29%), have led to distinct and sharp symmetrical CPL in the ultraviolet and visible regions, with dissymmetry factors ( g lum ) of ∼2 × 10 –3 and ∼4 × 10 –3, respectively. This work has established and expanded the materials space for chiral RE metal halides and demonstrated their potential for chiroptical and spintronic applications.