Multicolor Circularly Polarized Photoluminescence and Electroluminescence with 1,2-Diaminecyclohexane Enantiomers

Development
of simple chiral materials with tunable circularly polarized photoluminescence
(CPPL) and circularly polarized electroluminescence (CPEL) for efficient
circularly polarized organic light-emitting diodes (CP-OLEDs) is the
key toward future 3D displays. In this study, four pairs of chiral
1,2-diaminocyclohexane-based fluorescence enantiomers were efficiently
prepared with high yields (up to 92%) and enantiomeric excesses (ee
>99%). By the introduction of N-methyl, carbazole,
and diphenylamine-donating groups, these materials showed multicolor
CPPL and CPEL from blue (420 nm) to red (610 nm) with good thermal
and conformational stability. The multilayer CP-OLEDs based on these
enantiomers show high external quantum efficiency of up to 5.5% with
low-efficiency roll-off and microimage circularly polarized electroluminescence
with a dissymmetry factor (gEL) of up
to −1.4 × 10–3/+1.3 × 10–3. These results push forward the development of future multicolor
circularly polarized electroluminescent materials.