Chiral Rare-Earth (Ce, Eu) Metal Halides with Bright Circularly Polarized Luminescence

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.