Circularly polarized electroluminescence from topologically chiral [2]catenane-based neutral radicals with tunable deep-red emission

Stable organic radicals with unique luminescence have demonstrated great importance in photoelectromagnetic materials and have found broad applicability in the field of organic light-emitting diode (OLEDs). Aiming to further extend their application into chiral optoelectronic devices, by employing topologically chiral [2]catenane as the key chiral skeleton, this work presents the first successful construction of circularly polarized OLEDs (CP-OLEDs) based on donor–acceptor (D–A•) type neutral tris(2,4,6-trichlorophenyl)methyl (TTM) radicals. Remarkably, the topologically chiral skeleton, in combination with its controllable dynamic features, enables the system to exhibit a luminescence dissymmetry factor (|gPL|) value as high as 7.1 × 10-3, as well as reversible circularly polarized luminescence (CPL) on/off switching in film state. Importantly, the resulting CP-OLEDs exhibit deep red emission, a maximum external quantum efficiency (EQEmax) of 3.92%, and a |gEL| value of 7.2 × 10-3. These findings demonstrate the successful development of not only luminescent radicals with unique switchable CPL performances, but also the first CP-OLEDs with promising device performance based on topologically chiral radical emitter, providing a distinctive design principle and a versatile platform for the creation of next-generation smart CP-OLEDs. Organic radicals can emit light but extending them to chiral optoelectronics with controllable circular polarization remains challenging. Wang et al. build topologically chiral catenane-based radical emitters and demonstrate efficient deep-red devices with switchable circularly polarized emission.