Spatial and dimensional tuning of gold nanoparticles for plasmonic enhancement in top-emission OLEDs

Plasmonic nanostructures have garnered significant interest for their ability to manipulate light at the nanoscale, offering potential performance enhancements in organic light-emitting diodes (OLEDs). In this study, we explore the spatial and dimensional effects of gold nanoparticles (AuNPs) in top-emission OLEDs (TEOLEDs) with a micro-cavity architecture. By varying the diameter (10, 50, and 90 nm) and vertical position of AuNPs—either near the emissive layer (EML) or adjacent to the anode— we observe position- and size-dependent plasmonic interactions, governed by near-field enhancement and far-field scattering. Notably, AuNPs positioned near the EML induce pronounced near-field coupling, with 50 nm particles exhibiting optimal enhancement in electroluminescence and radiative decay rate, as confirmed by time-resolved photoluminescence (TRPL) and optical simulations. In contrast, AuNPs near the anode show minimal impact, dominated by far-field scattering. These findings demonstrate that precise engineering of nanoparticle location and size is essential for harnessing plasmonic effects in micro-cavity OLEDs, enabling efficient light management and device optimization.