Synthesis of poly(3,4-ethylenedioxythiophene) : poly(styrene sulfonate)-capped silver nanoparticles and their application to blue polymer light-emitting diodes

Abstract

Organic light-emitting diodes (OLED) and polymer light-emitting diodes (PLED) are promising candidates for future display applications due to their superior properties, but their efficiency and stability need to be improved to expand their application to large-size display panels and lightings. One of the most remarkable ways to enhance the efficiency of PLEDs is to incorporate metal nanoparticles and utilize their localized surface plasmon resonance (LSPR). We report on the improvement of blue PLEDs efficiency by the insertion of silver nanoparticles (Ag NPs) capped by poly(3,4-ethylenedioxythiophene) : poly(styrene sulfonate) (PEDOT : PSS). Ag NPs were synthesized with PEDOT : PSS as a stabilizer and then deposited on an indium tin oxide (ITO) anode using a simple spin-coating process without any aggregation. The result of deposition was confirmed by SEM and TEM images, and by Raman spectrum. Optical properties of the PEDOT : PSS-capped Ag NPs on ITO and the interaction between Ag NPs and Lumation blueJ, a blue light-emitting polymer, were measured using a UV-Vis spectrophotometer, a photoluminescence (PL) spectrophotometer, and a time-resolved photoluminescence spectrophotometer (TRPL). As a result, the introduction of PEDOT : PSS-capped Ag NPs to the blue PLEDs was found to have been successfully conducted. The fabricated blue PLEDs with Ag NPs exhibited a 15% increase of external quantum efficiency. This was thought to originate from the localized surface plasmon coupling of the PEDOT : PSS-capped Ag NPs with Lumation BlueJ.