Small organic molecules for circularly polarized luminescence: from design to applications

Circularly polarized luminescent-active small organic molecules (CPL-SOMs) exhibit broad application prospects in 3D displays, information encryption, biosensing, and circularly polarized organic light-emitting diodes (CP-OLEDs), owing to their simple and readily modifiable molecular structures, high luminescence efficiency and well-defined structure-property relationships. Nevertheless, the luminescence dissymmetry factor (g _lum) of most CPL-SOMs remains in the range of 10^-3-10^-5, significantly below the theoretical maximum. Therefore, enhancing the g _lum value remains a top priority. Achieving effective regulation of CPL signals is also an important research direction, thereby enabling further expansion of their applications into emerging fields such as smart sensing and security technologies. This review focuses on recent research advances in high-performance CPL-SOMs, covering design strategies for central chiral, axially chiral, helical chiral, and planar chiral systems, as well as their photophysical and chiroptical properties and device performance. Finally, the current challenges and future research directions for these materials are discussed, with the aim of providing valuable references for the development of high-performance chiral optoelectronic organic molecules.