Photon recycling effect in perovskite LEDs and solar cells

Perovskites are emerging as promising materials for both solar cells and light-emitting diodes (LEDs). Despite the impressive electroluminescence efficiencies demonstrated by perovskite LEDs, their device designs still largely rely on classical optics, similar to previous organic LEDs. In this work, the focus is on the role of photon recycling in perovskite electroluminescence. A novel optical modeling approach is introduced, which accounts for the reabsorption properties of luminescent materials. This analysis reveals that photon recycling can significantly enhance the electroluminescence efficiencies of perovskite LEDs, surpassing previous limits for outcoupling. This model elucidates how recent advancements in perovskite LEDs have achieved such high efficiencies, despite the challenges posed by the high refractive index of perovskites. Moreover, it is discovered that photon recycling has an even more pronounced effect in perovskite solar cells with thicker active layers. This suggests that perovskite solar cell architectures hold potential for generating very bright electroluminescence, potentially surpassing even state-of-the-art perovskite LEDs.