Toward Rhenium‐based Circularly Polarized OLEDs Using Tailored Chiral Re(CO)3 Emitters

Chiral rhenium(I) emitters showing circularly polarized phosphorescence (CPP) are an attractive mainstay for CP organic light‐emitting diodes (CP‐OLEDs). However, the efficiency of such emitters is not ideal, and they have never been explored for circularly polarized electroluminescence (CPEL) applications. Here, we have tailored robust chiral Re(I) complexes with improved CPP properties, and firstly demonstrated CPEL from rhenium emitters. The designed chiral Re(I) complexes exhibit a yellow CPP with enhanced |glum| factors (up to 2.5×10–2) and a good quantum efficiency. The pioneering Re(I)‐based CP‐OLEDs (based on the obtained emitters) exhibit yellow CPEL with |gEL| factors of up to 6.2×10–3 and maximal external quantum efficiency of 13.2%. Furthermore, we have demonstrated for the first time a suppressive effect of a magnetic field on the CPP strength of Re(I) emitters. This work highlights the good potential of chiral Re(I) emitters for CPEL applications, and opens up a new shortcut to CPP‐active Re(I) complexes.