Circularly Polarized Phosphorescent Electroluminescence with a High Dissymmetry Factor from PHOLEDs Based on a Platinahelicene

TLDR

Circularly polarized light is sought for quantum computing, spintronics, biomedicine, and displays, yet CP‑phosphorescent OLEDs remain underexplored and previous devices suffered from low brightness or dissymmetry. The authors aim to develop a CP‑phosphorescent OLED that delivers display‑level brightness and a high dissymmetry factor. They construct a single‑layer device using a platinahelicene complex as the emissive material. The device achieves a dissymmetry factor high enough to offer real‑world advantages over nonpolarized emission, demonstrating the feasibility of chiral metal‑complex CP‑PHOLED displays.

Abstract

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-of-concept single-layer helicene-based device is sufficient to provide real-world benefits over nonpolarized emission and paves the way toward chiral metal complex-based CP-PHOLED displays.