On‐Demand Circularly Polarized Room‐Temperature Phosphorescence in Chiral Nematic Nanoporous Silica Films

Abstract Circularly polarized room‐temperature phosphorescence (CPRTP) is of paramount importance for applications in information encoding, bioimaging, and optoelectronic devices, however, it remains challenging to organize highly efficient CPRTP materials with controlled handedness and long afterglow. Herein, as an outstanding novel finding, it is diclosed that ultralong CPRTP with on‐demand chiroptical properties is simple to realize using the earth‐abundant cellulose and silica. It is shown that left‐handed chiral nematic nanoporous silica films featuring defect photoluminescence enable ultralong CPRTP with an unprecedented control of the handedness. This work presents that the chiral nematic nanoporous silica films display right‐handed CPRTP and left‐handed CPRTP with the phosphorescence dissymmetry factors up to −0.130 and 0.093 as well as the afterglow lifetimes of 1.094 and 0.949 s, respectively. The potential of the transparent chiral nematic nanoporous silica films, capable of ultralong CPRTP and selective reflection of left‐handed circularly polarized light, for the development of anticounterfeiting optical labels is showcased. This work presents a versatile strategy and a step toward the development of ultralong CPRTP materials with on‐demand chiroptical properties from readily available defect phosphors for photonic applications.