Tunable circular polarization room temperature phosphorescence with ultrahigh dissymmetric factor by cholesteric liquid crystal elastomers

Abstract

It is highly demanded that organic functional materials that can generate strong and switchable circularly polarized room temperature phosphorescence (CPRTP) be developed. Here, we report a simple and effective strategy to achieve mechanical-tunable CPRTP with high and switchable luminescence dissymmetric factors (glum) by doping a bulky phosphorescent guest, tetra-N-phenylbenzidine (TPB), into reconfigurable cholesteric liquid crystal elastomers (CLCEs). The amount of chain extender plays a vital role in determining the phosphorescent lifetime and mechanical properties in the constructed CLCE composite films. Both the experimental and theoretical results reveal that the bulky TPB compensates for the insufficient rigidity of the CLCEs, resulting in a long-afterglow CPRTP. Moreover, the glum of CPRTP can be tuned from 0.93 to near zero by stretching the CLCEs. Combining the CLCEs’ reconfigurable network and remarkable CPRTP, a 4D encryption luminescent barcode is established, exhibiting great potential for information storage and encryption of these distinct materials.