Nanoimprinted DMD Electrodes Enabling Bidirectional Viewing OLEDs With Quasi Lambertian Emission

ABSTRACT Bidirectional displays, capable of simultaneous front and rear illumination, enable transformative applications such as see‐through retail displays, intelligent signage, and next‐generation foldable devices. Despite their potential, the inherent trade‐off between transparency and brightness, coupled with imbalanced bidirectional emission, has hindered the advancement of bidirectional viewing organic light‐emitting diodes (BV‐OLEDs). Here, we present a dual‐approach strategy to achieve simultaneously improved and balanced bidirectional emission with quasi‐Lambertian distribution in bidirectional emitting OLEDs. By combining a microcavity resonance enhancement through nano‐patterned structures and a dielectric/metal/dielectric (DMD) capping layer for improved top electrode transmittance, we effectively suppress surface plasmon and waveguide modes in OLED devices. Consequently, the optimized nanoimprinted DMD electrode achieved a remarkable 89.7% enhancement in transmittance (from 33.9% to 64.3% at 664 nm) compared to conventional planar electrodes; and the resulting BV‐OLED demonstrated balanced bidirectional emission from 33% to 42% with a 67.3% total brightness increase, while exhibiting enhanced transparency with nearly zero haze, quasi‐Lambertian radiation pattern, and excellent color stability across a 120° viewing angle. This breakthrough establishes a fundamental design framework for bidirectional displays, bridging conventional dual‐panel technologies with emerging applications in next‐generation transparent and flexible display systems.