Multi-Color Circularly Polarized Room-Temperature Phosphorescence from Processable Chiral Photonic Films

Abstract

Circularly polarized luminescence (CPL) plays a crucial role in chiral science and photonic technologies. However, developing multi-color and tunable circularly polarized room temperature phosphorescence (CP-RTP) materials with high luminescent dissymmetric factor (g_lum) and superior processibility remains challenging. Here, an effective strategy is demonstrated to construct remarkably processable chiral photonic films that exhibit multi-color tunable CP-RTP characteristics by incorporating RTP polymers into cholesteric cellulose nanocrystals (CNCs) with the assistance of D-(+)-glucose (Glu). The Glu is especially selected to prepare flexible and iridescent colors of responsive photonic CNC-RTP films and modulate the photonic band gaps (PBGs) of the CNCs via hydrogen-bonding interactions. The tunable PBGs allow for flexible control of the wavelength and handedness of CP-RTP while achieving a high |g_lum| value of up to 0.59 and a long phosphorescence lifetime of 371 ms. Importantly, 3D arbitrarily patterned CP-RTP films with excellent processability and multiple polarized characteristics are demonstrated. Furthermore, by leveraging structural colors, fluorescence, long phosphorescence lifetimes, circular polarization characteristics, and time-dependent afterglow properties of these CP-RTP films, multilevel data encryption applications are also presented. These sustainable and scalable CP-RTP materials with remarkable processibility, present novel opportunities and pave the way for diverse technological applications in information processing and multilevel information encryption.