Effect of coupling between excitons and gold nanoparticle surface plasmons on emission behavior of phosphorescent organic light-emitting diodes

Abstract Enhanced efficiency and reduced efficiency roll-off in phosphorescent organic light-emitting diodes (PhOLEDs) are realized by interposing a solution-processed gold nanoparticle (GNP)-based interlayer between the anode and the hole-injection layer. Transient photoluminescence measurements elucidate that a reduced lifetime of the triplet excitons was observed for samples having a GNP-interlayer as compared to a control sample without the GNP-interlayer. The decrease in the triplet exciton lifetime, caused by the coupling between the triplet excitons and the localized surface plasmons (LSPs) excited by the GNPs, enables reducing the triplet–triplet and triplet–polaron annihilation processes, thereby a reduced efficiency roll-off in PhOLEDs. The presence of a GNP-interlayer also acts as an optical out-coupling layer contributing to the efficiency enhancement and was demonstrated by the theoretical simulation.