Polarization-selective photon recycling microcavity for efficient polarized quantum-dot LEDs

The simultaneous realization of high external quantum efficiency (EQE) and high degree of polarization (DoP) in circularly polarized light-emitting diodes (LEDs) remains a substantial challenge. Here, we present a polarization-selective photon recycling microcavity integrated into a top-emitting quantum-dot LED (TE-QLED). The device incorporates a chiral Bragg-specular reflection microcavity, in which light with the opposite handedness to the Bragg layer is transmitted directly, whereas light with the same handedness undergoes chirality reversal and exits the microcavity with the opposite handedness. This polarization-selective photon recycling mechanism enables the recovery of photons that would otherwise be lost in conventional polarized light generation, thereby overcoming the physical limit of 50% loss in polarized emission. As a result, a circularly polarized QLED with a DoP of 81% (electroluminescence dissymmetry factor g_lum(EL) = 1.62) and a high EQE of 20.27% is achieved, with only 17.8% light loss compared to the reference device. Furthermore, a proof-of-concept three-dimensional display prototype is demonstrated, highlighting the potential of this approach for advanced display technologies.