Simulation Of Enhanced Light Extraction From Periodic, Disordered, And Quasi-Periodic Oled Structures

We have developed a rigorous scattering matrix theory of light emission from periodically structured media using a Green's function approach. We computationally simulate the spectral power inside the structure, incorporating Purcell factor enhancements, and find internal waveguiding modes and plasmonic losses. We simulate the light-outcoupling factor eta(out) and describe how corrugations and structured media can enhance eta(out). We have extended our framework to describe non-periodic disordered arrays aswell as aperiodic quasi-crystalline arrays. Flat organic light-emitting diodes (OLEDs) have low outcoupling with eta(out) similar to 20% since most of the light is trapped in waveguided modes in higher index layers or lost to plasmonic excitations at the metal cathode. Periodically corrugated OLEDs can achieve highly enhanced eta(out) similar to 65%-70% for pitch values between 1000 and 2000 nm, representing an enhancement factor > 3 over planar structures. Periodic corrugations strongly diffract trapped waveguided and plasmonic modes to the emissive air cone. Disordered templates also can cause significant enhanced outcoupling with eta(out) similar to 50%-55% for smaller nearest-neighbor separations of 300-400 nm. Quasi-crystalline tilings can also lead to enhancements of eta(out) similar to 50%-55%. This framework can be utilized to design novel structured media that can generate high light extraction. (C) 2021 Optical Society of America