ABSTRACT

Perovskite quantum dot light-emitting diodes (PeQLEDs) are promising for display and lighting applications. As internal quantum efficiencies approach 1, enhancing photon extraction becomes critical due to severe optical losses. Herein, we proposed a facile ligand exchange strategy with bifunctional 1,5-naphthalenedisulfonic acid (NDSA) to modulate the orientation of transition dipole moments (TDMs) of the originally isotropic emissive layers composed of cubic perovskite nanoparticles (NCs). Incorporation of the NDSA significantly enhanced the long-range packing order of NCs, leading to an increase in the proportion of horizontal TDMs in the NCs film from 60% to 70%. This improved orientation was instrumental in enhancing light outcoupling efficiency (η_out) from 16.15% to 20.09%. As a result, devices with NDSA modified exhibit a peak external quantum efficiency (EQE) of 22.63% at 5,127 cd/m² and a maximum luminance of 13,950 cd/m², significantly outperforming the pristine device. EQE remains above 20% across 400-8,000 cd/m², and device lifetime improves by 400%.

In Submission (2025. 09. 03)

In Revision (2025. 11. 24)

doi.org/10.1002/adma.202517210