Microcavity forming electrode for efficient color-tunable semitransparent perovskite light-emitting diodes

Perovskite light-emitting diodes (PeLEDs) have shown excellent optical properties and exhibit great potential for application in daily life. PeLEDs based on bottom-emitting structures have gained a boost improvement in efficiency and application. However, research on transparent PeLEDs is lagging due to the hysteresis of transparent electrodes, which has become one of the main obstacles for potential practical display applications. Here, we demonstrate novel color-tunable semitransparent PeLEDs with a maximum transmission of 49.6% by adopting the microcavity structure of Mg:Ag/2,2',2"-(1,3,5-benzinetriyl)-tris(1-phenyl-1-H-benzimidazole) (TPBi)/Mg:Ag as the electrode, where the reflection and transmission spectra could be precisely tuned by adjusting the thickness of the medium layer in the microcavity structure. The PeLED with a microcavity structure as the electrode achieved a peak external quantum efficiency (EQE) of 12.5% and maximum luminescence of 13000 cd cm-2. The PeLED based on a microcavity structure electrode shows promising potential applications in display and illumination due to its high transmittance and efficiency.