A research team led by Prof. DUAN PengFei from the National Center for Nanoscience and Technology (NCNST) proposed an effective approach for achieving upconverted circularly polarized ultraviolet luminescence (UC-CPUVL) with larger circular polarization by integrating visible-to-UV triplet-triplet annihilation photon upconversion (TTA-UC) and chiral liquid crystal. In addition, the UC-CPUVL emission has been used to trigger the enantioselective photopolymerization of diacetylene. This study was published in “Nature communications”. Article link: https://www.nature.com/articles/s41467-020-19479-1.
Figure 1. The process of sequentially amplified circularly polarized ultraviolet luminescence (CPUVL).
Chiral functional materials with circularly polarized luminescence (CPL) have risen rapidly because of their potential applications in various research fields. However, limited to the small luminescence dissymmetry factor (glum), practical application examples have rarely been reported.
Herein, scientists reported one interesting example of visible-to-UV UC-CPUVL, which was composed of chiral annihilator R(S)-4,12-biphenyl[2,2]paracyclophane and achiral sensitizer thermally activated delayed fluorescence (TADF) molecule 4CzIPN. Interesting, after embedding this upconversion pairs into a room-temperature nematic liquid crystal, induced chiral nematic liquid crystal (N*LC) and high-performance UC-CPUVL could be obtained. It’s worth mentioning that the glum value reached to 0.19. More importantly, taking a step forward, the UC-CPUVL emission generated from N*LC, has been successfully used to trigger the enantioselective polymerization of diacetylene with great stereoselectivity.
This work will not only provide the proof-of-concept for the usage of TTA-UC for challenging chiral polymerization and paves the way for the further development of functional application of CPL active materials.
This work was supported by the Strategic Priority Research Program of Chinese Academy of Sciences; the Ministry of Science and Technology of China, National Natural Science Foundation of China.
Figure 2. UC-CPUVL triggered enantioselective photopolymerization.