Upconverting and downshifting circularly polarized luminescence in a superstructural helix  

作　　者：Honghan Ji Bin Wu Enquan Tian Chao Ren Xue Jin Liangliang Zhu Pengfei Duan 

机构地区：[1]CAS Key Laboratory of Nanosystem and Hierarchical Fabrication,National Center for Nanoscience and Technology(NCNST),Beijing 100190,China [2]State Key Laboratory of Molecular Engineering of Polymers,Department of Macromolecular Science,Fudan University,Shanghai 200438,China [3]University of Chinese Academy of Sciences,Beijing 101408,China

出　　处：《Science China Chemistry》2024年第8期2571-2577,共7页中国科学（化学英文版）

基　　金：supported by the National Natural Science Foundation of China (52173159, 92256304);the National Key Basic R&D Program of Ministry of Science and Technology of the People’s Republic of China (2021YFA1200303);the Strategic Priority Research Program of Chinese Academy of Sciences (XDB36000000);the Beijing Municipal Science and Technology Commission (JQ21003)。

摘　　要：The modulation of circularly polarized luminescence(CPL) has become an increasingly prominent area of research. In this study,we propose a unique “one-excitation-to-three-emissions” CPL system through the co-assembly of an upconversion system,incorporating one sensitizer(Pt(II) mesotetraphenyl tetrabenzoporphyrine, Pt TPBP) and two annihilators(R/S-DPA and R/SBDP) within liquid crystals. The chiral nature of the annihilators induces a transformation of the nematic liquid crystal into chiral nematic liquid crystals(N*LC), establishing an excellent chiral matrix. Upon the incorporation of the sensitizer Pt TPBP and subsequent excitation at 635 nm, the system demonstrates two independent triplet–triplet annihilation photon upconversion(TTA-UC) with the emission in blue and yellow, aided by thermally activated triplet–triplet energy transfer(TTET). This is accompanied by the simultaneous generation of upconverting circularly polarized luminescence(UC-CPL) and downshifting near-infrared circularly polarized luminescence(DS-CPL) originating from the residual luminescence of Pt TPBP. Remarkably,fine-tuning the ratio between the two annihilators allows the TTA-UC system to exhibit multicolor CPL emission with an amplified luminescence dissymmetry factor(glum, reaching up to 0.6). Our study unveils a previously unreported “one-excitation-to-three-emissions” system and provides a versatile strategy for modulating CPL emissions, surpassing conventional methodologies.

关 键 词：circularly polarized luminescence triplet–triplet annihilation upconversion near-infrared emission chiral nematic liquid crystal luminescence dissymmetry factor 

分 类 号：O436.3[机械工程—光学工程] O734[理学—光学]