Enhancing light out-coupling in flexible organic light emitting devices through the localized surface plasmon resonance of urchin-like gold nanoparticles

The local surface plasmon resonance (LSPR) effect and scattering properties of gold nanoparticles are effective ways to improve the light extraction efficiency of organic light-emitting diodes (OLEDs). Here five different kinds of urchin-like gold nanoparticles (UGNs) were synthesized using the seed-mediated method. The finite-difference time-domain (FDTD) method was used to calculate the near-field local and far-field scattering properties of various sea urchin-like gold nanoparticles. All five types of UGNs demonstrated certain levels of light enhancement within the visible band. The flexible OLED devices were created by doping five different types of nanoparticles into the flexible substrates. The hollow UGNs device exhibited a maximum current efficiency of 124.25 cd/A, a maximum power efficiency of 131.27 lm/W, and a maximum EQE of 45.54 %. When compared to undoped flexible devices, the maximum current efficiency, the maximum power efficiency, and the maximum EQE increase by 132 %, 82 %, and 36 %, respectively. The results indicate that combining the flexible conductive substrate and UGNs is an effective strategy for improving light extraction from flexible OLEDs. This enhancement effect originates from UGNs acting as a scattering layer to reduce total light reflection, and the luminous intensity of the device is improved due to the LSPR of sea urchin-like nanoparticles.