Simulation of Surface Plasmon Coupled Conjugate Polymer for Polymer Light-Emitting Diodes

Abstract

Since 1977, conjugated polymers have received attention as materials for display devices with a low-cost solution process, but the low efficiency of these materials has been considered as a drawback which should be overcome. Nowadays metal nanoparticles are inserted on the display device's cathode to overcome the low efficiency of the materials through the enhanced coupling between the Localized surface plasmon resonance (LSPR) and exciton in emitting material [1]-[4]. In our previous work, conjugated polymer with an imprinted regular Ag-dot-array structure showed a 2.7-fold improvement of integrated photoluminescence (PL) intensity [1], but the result was not optimized. Therefore, in this study, we calculated the Ag-dot-array absorbance-peak shift in detail using finite-difference time-domain (FDTD) simulation and found the absorbance peak location which maximized photoluminescence (PL) intensity, depending on various Ag dot condition. The resulting information was applied to the previous structure [1]. Thus, we reduced the trial and error of finding the optimized absorbance peak location and the imprint processing costs. The most important parameter of the Ag-dot-array absorbance peak was the lattice constant. Furthermore, we proved the indium tin oxide (ITO) waveguide effect in our structure using FDTD.