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)4Cu4I8·2H2O (MBA = α-methylbenzylaminium)
and acentric Gua6Cu4I10 (Gua = guanidinium)
single crystals were grown on the basis of Gua3Cu2I5 by the slow evaporation method. (R/S-MBA)4Cu4I8·2H2O single crystals
exhibited excellent circularly polarized luminescence (CPL) characteristics.
More importantly, ultraviolet-pumped LEDs (UV-LEDs) based on (R/S-MBA)4Cu4I8·2H2O and Gua6Cu4I10 single crystals exhibit a higher
optical selectivity when exposed to right-handed and left-handed circular
polarization (RCP and LCP) conditions. (S-MBA)4Cu4I8·2H2O single crystals and Gua6Cu4I10 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.