Anomalous circularly polarized light emission caused by the chirality-driven topological electronic properties

Chirality of organic molecules is characterized by selective absorption and emission of circularly-polarized light (CPL). A consensus for chiral emission (absorption) is that the molecular chirality determines the favored light handedness regardless of the light-emitting (incident) direction. Refreshing above textbook knowledge, we discover an unconventional CPL emission effect in organic light-emitting diodes (OLEDs), where oppositely propagating CPLs exhibit opposite handedness. This direction-dependent CPL emission boosts the net polarization rate by orders of magnitude in OLED devices by resolving the long-lasting back-electrode reflection problem. The anomalous CPL emission originates in a ubiquitous topological electronic property in chiral materials, i.e., the orbital-momentum locking. Our work paves the way to design novel chiroptoelectronic devices and reveals that chiral materials, topological electrons, and CPL have intimate connections in the quantum regime.

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