Circularly polarized luminescent nanoparticles: preparation, performance and applications

Circularly polarized luminescence (CPL) represents a unique optical phenomenon where emitted light exhibits a specific circular polarization, offering significant advantages in advanced photonic applications. Luminescent nanoparticles capable of CPL have garnered increasing attention due to their potential in enhancing display technologies, bioimaging contrast, and quantum information processing. Despite rapid progress, challenges still remain in synthesizing nanoparticles with high CPL efficiency, good stability, and tunable optical properties. The interplay between nanoparticle size, morphology, and chiral surface functionalization critically influences their luminescence and chiroptical performance. This review comprehensively discusses recent advances in the preparation, performance, and applications of CPL-active nanoparticles. Key synthetic strategies including molecular self-assembly, chiral ligand functionalization, chiral environment induction, and hybrid organic-inorganic approaches are detailed, highlighting how they enable precise control over CPL properties. Critical performance metrics such as dissymmetry factor (g_lum), quantum yield, and circularly polarized luminescence brightness (B-CPL) are examined, alongside the influence of nanoparticle size, morphology, and environmental factors on CPL efficiency. The review also introduces emerging applications in optical displays, stimuli-responsive sensing, multilevel data encryption, and bioimaging, underscoring the role of CPL nanoparticles in developing next-generation photonic and optoelectronic devices. Finally, current challenges and future directions for enhancing CPL performance and practical applicability are discussed.