Analyses of the light extraction efficiency of organic light-emitting diodes with ITO/mesh-Ag/ITO anode and its optical transmittance as transparent electrode

Abstract

We have used the three-dimensional finite-difference time-domain simulation method to analyze the out-coupling efficiency of organic light-emitting diodes (OLEDs) with an ITO/Mesh-Ag/ITO anode. The period and grid space of the meshed Ag structure effectively affected the extraction ratio (ER) of the bottom-emitting OLED. The 3D simulation results for a simple structure of OLED with an ITO/Mesh-Ag/ITO anode showed the ER of about 26.4% and it enhanced 2.26 times that of the continuous Ag layer of about 11.7%. In addition, in respect to the transparent electrode of the OLED using the ITO/Mesh-Ag/ITO multiple layers, the Ag thickness and open ratio were important factors that affected the transmittance and the electrical conductance. The open ratio of 60% resulted in sheet resistance of less than 25 omega/, while keeping the transmittance nearly similar to that in the case of a single ITO layer.