Aggregation Induced Emission in Holographic Polymer Dispersed Liquid Crystals*

Holography is implemented through interference of several coherent laser beams. It can simultaneously reconstruct whole amplitude and phase information of light over a large area. This feature enables holography to prevent any illegal copying or scanning.
To improve the security of holograms, we combined fluorescence and holographic technology. Holographic polymer dispersed liquid crystal (HPDLC) was employed as the matrice considering its electro-optical response capability. Aggregation-induced emission (AIE) is a non-emissive luminogen in good solvent but able to emit strong fluorescence under aggregation. Results turn out that the fluorescence intensity of HPDLC increased linearly when increasing AIE concentration.
We also studied the effect of AIE on the diffraction efficiency(DE). When the AIE concentration increased from 0 to 3 wt%, the DE remained basically unchanged, but the DE decreased rapidly when further increasing AIE loading. The correlation between DE and AIE concentration satisfies Boltzmann equation. Where y and x represent the DE of HPDLC and AIE concentration, respectively. y=15.99+79.56/(1+exp((x-4.22)/0.59)