Induction of circularly polarized electroluminescence from achiral poly(fluorene--benzothiadiazole) by circularly polarized light

Circularly polarized luminescence is rising to be the cynosure of a range of display and photonic technologies, including backlights, optical spintronics, and quantum information processing. Conventional strategies to directly generate circularly polarized electroluminescence from the emissive layer (EML) of organic light-emitting diodes (OLEDs), including the attachment of chiral pendants and use of chiral additives, have been well developed. Herein, we demonstrate that OLEDs based on achiral poly(9,9-di- n -hexylfluorene- alt -benzothiadiazole) (F6BT) could be induced to directly give a preferential emission of left- or right-handed circularly polarized electroluminescence just by simple treatment with circularly polarized light. The screw sense in F6BT could be easily controlled, and exhibited a strong dependence not only on the handedness but also on the wavelength of the driving circularly polarized light. This study sheds light on a unique design to realize circularly polarized electroluminescence from achiral compounds and pave the way for the fabrication of large-area and high-quality chiral optoelectronic devices. Without any chiral additives, achiral F6BT could be induced to directly give a preferential emission of specific handed CP EL.