Fast Emission Color Switching of Circularly Polarized Luminescence in Platinum(II) Liquid Crystalline Co-Assembly

Abstract

Developing stimuli-responsive circularly polarized luminescence (CPL) materials that feature fast emission color switching for advanced information encryption presents a scientifically significant yet formidable challenge. Herein, we construct a supramolecular co-assembly system demonstrating transiently responsive CPL emission color switching, enabling mechanically-modulated information encryption. Combining a highly luminescent Pt(II) liquid crystal (Pt8) with the anchored binaphthyl inducers (R/S-M) form chiral co-assemblies (R/S-M)0.03-(Pt8)0.97, which assembles into twisted nanobelts (180 ºC) and helical nanofibers (260 ºC) exhibiting green (λem = 545 nm, gem = 0.038) and red CPL (λem = 640 nm, gem = 0.133), respectively. Notably, mechanical grinding transforms the 180 ºC-annealed (R/S-M)0.03-(Pt8)0.97 into nanoparticles, resulting in a fast dynamic switching of CPL emission color from green to orange-red (λem: 545 → 625 nm, gem: 0.038 → 0.058). Reheating the grinding films (R/S-M)0.03-(Pt8)0.97 to 180 ºC restores the initial green CPL of the nanobelts. Based on the fast CPL emission color switching, we demonstrate the applications of these supramolecular chiral co-assemblies for mechanically-modulated information encryption.