Emission behavior of dual-side emissive transparent white organic light-emitting diodes

White organic light-emitting diodes (WOLEDs) resemble light more naturally, with emission spectrum that is comfortable to the human eye. The transparent WOLEDs can be almost invisible by day and can emit a pleasant diffused light at night, allowing the surface light source to shine in both directions, an exciting new lighting technology that could bring new device concepts. However, undesirable angular-dependent emission in transparent WOLEDs is often observed, due to the microcavity effect. In this work, the emission behavior of dual-side emissive transparent WOLEDs was studied experimentally and theoretically. It is found that avoidance of the overlap between the peak wavelengths of the emitters and the resonant wavelength of the organic microcavity moderates the angular-dependent electroluminescence emission behavior, thereby improving the color stability of the transparent white WOLEDs over a broad range of the viewing angle.