Tunable Circularly Polarized Luminescence Triggered by Orientational Order Parameter of Achiral Dichroic Dyes in Cholesteric Liquid Crystal Medium

Abstract The regulation of circularly polarized luminescence (CPL) behavior of cholesteric liquid crystals (CLCs) by doping achiral dyes is of great significance for the development of real 3D application materials. However, current design strategies for CLCs materials are primarily focused on tuning helical structure, causing the inadequate investigation of fluorescence order parameters ( S F ) of achiral dyes on CPL signal regulation. Here, four achiral dichroic dyes with different S F values are developed in CLCs media. The CLCs system incorporating the p ‐C5PhHBT dye achieves the strongest g lum value of +0.48/−0.47, attributed to its highest order parameter ( S F = 0.56) in CLCs. Moreover, these four CLCs systems exhibit S F ‐dependent CPL properties with almost identical helical superstructures and pitches, highlighting the significant potential of S F regulation as a strategy for tuning CPL signals. Based on the similar fluorescence wavelengths and distinct CPL behaviors observed in CLCs, a concept for dual anti‐counterfeiting applications is further proposed.