Blue circularly polarized luminescence (CPL) is crucial for applications in full-color stereoscopic displays, polychromatic data recording, anti-counterfeiting, biological imaging, and optical communications. While various organic blue CPL materials (fluorescence, metal-complex, and thermally activated delayed fluorescence (TADF)) have been developed, creating blue circularly polarized organic afterglow (CPOA) materials with long lifetimes and effective chirality remains challenging. Three key requirements for CPOA are: effective chirality in the phosphor chromophores; enhanced triplet exciton generation via intersystem crossing (ISC); and stabilization of triplet excitons by suppressing non-radiative decay. Triplet excitons are easily lost through non-radiative transitions like triplet-triplet annihilation and luminescence quenching. Chiral crystal engineering, while promising, can lead to triplet-triplet annihilation and red-shifted afterglow emission, hindering the development of long-lived blue CPOA. In contrast, confining single molecules in a polymer matrix can lead to a blue-shifted emission and enhanced triplet exciton stabilization. This study proposes a strategy using the self-confinement of isolated chiral chromophores within a rigid polymer matrix to minimize non-radiative transitions and enhance blue CPOA. The resulting blue CPOA polymer demonstrates ultralong lifetimes (up to 3.0 s) and a high luminescent dissymmetry factor (g_lum = 1.02 × 10⁻²). Furthermore, synergistic afterglow and chirality energy transfer (SACET) allows for full-color CPOA polymers by doping with commercially available fluorescent molecules, enabling green, red, and even white CPOA emission.

The existing literature extensively covers various approaches to achieve circularly polarized luminescence (CPL), including fluorescence, metal-complex, and thermally activated delayed fluorescence (TADF) materials. However, the development of blue circularly polarized organic afterglow (CPOA) materials with long lifetimes and high dissymmetry factors has proven elusive. Previous methods such as chiral chain engineering, ionic co-crystals, polymerization, and host-guest strategies have shown some success, but limitations remain in achieving the desired blue emission with extended lifetimes and effective chirality. The challenge lies in simultaneously achieving high triplet energy levels to enable blue emission, suppressing non-radiative transitions that quench the afterglow, and incorporating sufficient chirality to generate circularly polarized light. The researchers highlight the limitations of previously employed techniques, particularly chiral crystal engineering, where ordered molecular packing can lead to energy loss and spectral shifts, making long-lived blue CPOA challenging. The current research aims to overcome these challenges by employing a novel self-confinement approach.

A series of CPOA polymers, *R*/S-PAMCOOCZ_X (X = 1–4), were synthesized via radical copolymerization. *R*/S-2-((2-(9H-carbazol-9-yl)propanoyl)oxy)ethyl acrylate (*R*/S-VCOOCZ), a blue light-emitting monomer with good phosphorescent properties and chirality, was selected. Polyacrylamide (PAM), with its carbonyl and amino groups, served as the polymer matrix. PAM promotes intersystem crossing (ISC) for triplet exciton generation and forms a strong hydrogen-bonding network to confine the chromophore, suppressing non-radiative decay. Chiral resolution yielded R-VCOOCz and S-VCOOCz with high enantiomeric excess (99.9% and 98.1%, respectively). The polymers *R*/S-PAMCOOCZ_X were synthesized with varying molar feed ratios of *R*/S-VCOOCZ and acrylamide (AM). Structural characterization was performed using nuclear magnetic resonance spectroscopy, powder X-ray diffraction, and gel permeation chromatography. Photophysical properties were investigated using steady-state and delayed PL spectroscopy, time-resolved emission spectroscopy, CPL spectroscopy, and CD spectroscopy. To demonstrate synergistic afterglow and chirality energy transfer (SACET), commercially available water-soluble fluorescent dyes (fluorescein sodium (Fluc), rhodamine 123 (Rh123), and sulforhodamine (SR101)) were incorporated into the blue CPOA polymers. The resulting full-color CPOA materials were characterized using similar techniques to assess their photophysical and CPL properties. Finally, applications of the CPOA polymers were demonstrated by fabricating multicolor Morse codes using screen printing, functional fibers by soaking cotton fibers in the polymer solution, and three-dimensional objects by casting the polymer solution.

The study successfully synthesized blue CPOA polymers (*R*/S-PAMCOOCZ₂) exhibiting ultralong lifetimes (3.0 s) and a high luminescent dissymmetry factor (g_lum = 1.02 × 10⁻²). The optimal molar feed ratio of *R*/S-VCOOCZ to AM was found to be 1:100. The blue afterglow emission peaks at 414, 442, and 470 nm originate from the isolated chiral *R*/S-VCOOCZ chromophore, as confirmed by low-temperature spectroscopy and wide-angle X-ray scattering. The SACET strategy effectively transferred energy from the blue CPOA host to various guest fluorescent dyes, resulting in tunable afterglow emission colors from yellow-green (Fluc), orange (Rh123), and red (SR101). The afterglow ET efficiency was significantly higher (64.3%) than the fluorescence ET efficiency (27.1%). Chiral characteristics were successfully transferred to the guest dyes, as demonstrated by CPL measurements. Furthermore, white CPOA emission was achieved by carefully controlling the concentration of Rh123. The water-soluble nature of the polymers allowed for straightforward fabrication of various applications, including multicolor Morse code encryption, functionalized fibers, and three-dimensional objects with tunable afterglow colors.

This research successfully addresses the challenge of creating high-performance blue CPOA materials. The self-confinement strategy effectively stabilizes triplet excitons, leading to ultralong lifetimes and high g_lum values. The SACET mechanism allows for precise control over the afterglow color, enabling full-color CPOA systems. This approach overcomes the limitations of previous methods by preventing aggregation-induced quenching and red-shifts in emission. The water-solubility of the materials further simplifies fabrication, opening up diverse applications. The results demonstrate a significant advancement in the field of CPOA materials, paving the way for broader applications in areas such as advanced displays, data storage, anti-counterfeiting, and sensing.

This study successfully demonstrated a novel approach for creating robust blue CPOA materials with ultralong lifetimes and high g_lum values through self-confining isolated chiral chromophores within a polymer matrix. The SACET strategy facilitated full-color CPOA emission, enabling the creation of multifunctional devices such as encrypted codes, functional fibers, and 3D objects. This research offers a new paradigm for designing and synthesizing high-performance CPOA materials and opens up avenues for diverse applications.

While the study demonstrates significant progress, some limitations exist. The efficiency of energy transfer via SACET may vary depending on the specific fluorescent dye used, requiring optimization for each color. Further investigation is needed to explore the long-term stability and robustness of the CPOA materials under various environmental conditions. The scalability of the synthesis method and the cost-effectiveness of the materials should also be considered for commercial applications.