Area-selective external light extraction for metal bus equipped large area transparent organic light-emitting diodes

Abstract

Area-selective external light extraction films based on wrinkle structured films were applied to large transparent organic light-emitting diodes (TOLEDs) with auxiliary metal buses. To be specific, on the external surface of the glass, we selectively formed a wrinkle structured film, which was aligned to the auxiliary metal electrodes. The wrinkle-structured film was patterned using a photo-mask and UV curing, which has the same shape of the auxiliary metal electrodes. With this area-selective film, it was possible to enhance the external quantum efficiencies of the bottom and top emissions TOLEDs by 15.7% and 15.1%, respectively, without significant loss in transmittance. Widened angular luminance distributions were also achieved in both emissions directions.

Enhanced light extraction from green organic light-emitting diodes by attaching a high-haze random-bowls textured optical film

“…Examples of internal light-extraction structures include optical gratings improving luminance efficiency by 72% [14], photonic crystals (∼38%) [15], random nano-structures (∼72%) [16], corrugated structures (35%) [17], nanoparticles (∼40%), moth-eye structures (69%) [18,19], and so on, which have reported extracting surface plasmon and waveguide modes. External light-extraction structures include a periodic microlens improving luminance efficiency by 47% [20], scattering films (∼31%) [21], wrinkle structured film (16%) [22], pyramid-based texture structure (∼30%) [23], etc. These structures are valid for coupling out the majority of substrate mode photons.…”