Circularly polarized (CP) light is of interest in
areas such as quantum optical computing, optical spintronics,
biomedicine and high efficiency displays. Direct emission
of CP light from organic light-emitting diodes (OLEDs) has
been a focus of research as it has the immediate application
of increasing efficiency and simplifying device architecture in
OLED based displays. High dissymmetry (gEL) factor values
have been reported for devices employing fluorescent polymers,
but these CP-OLEDs are limited in their ultimate efficiencies
by the type of emissive electronic transitions involved.
In contrast, phosphorescent OLEDs (PHOLEDs) can
emit light from triplet excited states and can therefore
achieve very high efficiencies. However, CP-PHOLEDs are
significantly understudied and the two previous reports suffered
from very low brightness or gEL values. Here, we use a
platinahelicene complex to construct a CP-PHOLED that
achieves both a display level brightness and a high gEL factor.
The dissymmetry of CP emission reached with this proof-ofconcept
single-layer helicene-based device is sufficient to
provide real-world benefits over non-polarized emission, and
paves the way towards chiral metal complex–based CPPHOLED
displays.