Improved Internal Quantum Efficiency and Light-Extraction Efficiency of Organic Light-Emitting Diodes via Synergistic Doping with Au and Ag Nanoparticles

This paper reports the distinct roles- of Au and Ag nanoparticles; (NPs) in organic light-Orating-diodes (OLEDS) depending on their sizes. Au and Ag-NPs that.are 40 arid 50 nm in size, respectively, are the most effective for enhancing the performance of green: OLEDs. The external quantum efficiencies (EQEs): of green OLEDs doped with An and Ag N.Pg, (40 and 50 rim, respectiVely) are improved by 29.5% and 36.1%, respectively, while the power. efficiencies (PE8) are enhanced by 47.9% and 37.5%, respectively. Furthermore, combining the Au and Ag NPs produces greater enhancements. The EQE and PE of the coci-oped OLEDs are improved by 63.9% and 68.8% respectively,-.through the synergistic behavior of the different NPs. Finite difference time-domain simulations confirm that the localized surfaee:plasmon resonance of the Au NPs near 580 nth improves the radiative recombination rate (k(rad)) of green-light emitters locally (<50 pm), while the Ag NPs cause relatively long, range and broadband enhancements in k(rad). The-Simulations of 'various domain sizes. Verify that the light-extraction efficiency (LEE),can, be enhanced by More than 4.2% by applying Ag NPS.. Thus, size-controlled Au and Ag NPs can synergistically enhance LEDS by improving both the internal quantum efficiency and LEE.