Enhanced light outcoupling in quantum-dot light-emitting diodes via polymer light scattering layers with embedded nanoparticles

Quantum-dot light-emitting diodes (QLEDs) inherently suffer from internal optical losses caused by wave-guided and surface plasmon polariton modes, which significantly limit their light outcoupling efficiency. To overcome this limitation, we developed and evaluated polymer-based light scattering layers embedded with aluminum oxide (Al2O3) nanoparticles, integrated into QLED structures externally on the substrate surface or internally beneath the cathode. External scattering layers enhanced luminous emittance by up to 78.2% by effectively redistributing emitted light toward broader viewing angles. And internal scattering layers – positioned adjacent to the bottom electrode – achieved notable improvements in luminance (32.9%) and current efficiency (up to 67.5%) without compromising device stability. Additionally, the concentration of Al2O3 nanoparticles critically influenced the scattering behavior and emission characteristics. These findings demonstrate that nanoparticle-dispersed polymer scattering layers offer a simple, scalable, and highly effective strategy, which is expected to help enhance light extraction in next-generation QLED display technologies.