High performance tandem perovskite LEDs through interlayer photon recycling

"Tandem light-emitting diodes (LEDs), achieved by vertically stacking multiple units in series to combine the luminance of individual light-emitting elements, are effective for improving efficiency and lifespan compared to single-unit devices13. In particular, tandem perovskite LEDs benefit from the small Stokes shifts of perovskites4, which in principle can enable significant photon recycling between individual perovskite layers and enhance light extraction from trapped modes. However, a tandem structure that effectively merges the luminance of each perovskite units still remains a significant challenge."

"Here, we demonstrate efficient and stable tandem LEDs by combining two solution-processed perovskite light-emitting units. This tandem structure effectively combines the original luminance of each light-emitting units; we argue that the emissions are also significantly enhanced through photon recycling between the individual light-emitting units. Consequently, we achieve tandem perovskite LEDs with a low turn-on voltage of 3.2 V, a high peak external quantum efficiency (EQE) of 45.5% (even 20% higher than the su"

Efficient and stable tandem LEDs are achieved by vertically stacking two solution-processed perovskite light-emitting units to combine luminance and improve device efficiency and lifespan. Small Stokes shifts in perovskites enable photon recycling between perovskite layers, enhancing light extraction from trapped modes and increasing emission intensity beyond additive effects. The tandem structure merges the original luminance of each unit while leveraging interlayer photon recycling for further enhancement. Resulting devices show a low turn-on voltage of 3.2 V and a high peak external quantum efficiency (EQE) of 45.5%, about 20% higher than single-unit counterparts.

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