Chiral Hybrid Copper(I) Iodide Single Crystals Enable Highly Selective Ultraviolet-Pumped Circularly Polarized Luminescence Applications

Light-emitting diodes (LEDs) with the circularly polarized luminescence features have attracted attention to the promising applications ranging from solid-state lighting and displays to bioencoding and anticounterfeiting. The prerequisite of circularly polarized luminescence is highly emissive chiral materials. Here, we demonstrated that (R/S-MBA) 4 Cu 4 I 8 ·2H 2 O (MBA = α-methylbenzylaminium) and acentric Gua 6 Cu 4 I 10 (Gua = guanidinium) single crystals were grown on the basis of Gua 3 Cu 2 I 5 by the slow evaporation method. (R/S-MBA) 4 Cu 4 I 8 ·2H 2 O single crystals exhibited excellent circularly polarized luminescence (CPL) characteristics. More importantly, ultraviolet-pumped LEDs (UV-LEDs) based on (R/S-MBA) 4 Cu 4 I 8 ·2H 2 O and Gua 6 Cu 4 I 10 single crystals exhibit a higher optical selectivity when exposed to right-handed and left-handed circular polarization (RCP and LCP) conditions. (S-MBA) 4 Cu 4 I 8 ·2H 2 O single crystals and Gua 6 Cu 4 I 10 single crystals induced by the (R)-MBA cation exhibit the different polarized light intensities at PL peak positions in different λ/4 waveplate polarizer angle directions, which provides new possibilities for the further applications from 3D displays to spintronics, as well as anticounterfeiting.