Advances in near-infrared circularly polarized luminescence with organometallic and small organic molecules

Circularly polarized luminescence (CPL) is an intriguing phenomenon characterized by the production of distinct emissions by chiral compounds when exposed to left- and right-handed circularly polarized luminescence. This phenomenon, distinguished by its ability to convey more intricate information and overcome angle dependence limitations associated with natural light, is progressively demonstrating its merits in diverse applications such as 3D optical displays, optical bio-probes, quantum communication, and asymmetric synthesis. The predominant focus of the current report centers on CPL materials within the visible region. However, it is noteworthy that Near-Infrared (NIR) emitters manifesting CPL characteristics hold substantial promise in diverse applications such as biological imaging, night vision, and organic light-emitting diodes. To address this, the present review systematically encapsulates research endeavors concerning NIR-CPL materials over last decades, systematically categorizing them into metal complexes and small organic molecule sections. Emphasis is placed on the exploration of extended emission wavelengths and the CPL performance exhibited by various classical molecular structures in the NIR spectrum. Furthermore, the review delves into methodologies aimed at enhancing CPL signals within the NIR emission region.