Researchers from Nankai University, Hebei University and King Saud University have developed a new strategy for fabricating all‑perovskite triple‑junction light‑emitting diodes (LEDs) that simultaneously emit red, green, and blue light. This breakthrough could mark a step toward high‑efficiency, full‑color back‑lighting for next‑generation ultrahigh‑definition (UHD) displays.
Triple‑junction tandem LEDs are widely seen as the ideal architecture for compact, energy‑efficient white light sources. However, stacking multiple metal halide perovskite layers through conventional solution processing often causes severe interlayer damage and carrier losses, making it difficult to maintain high efficiency across the junctions. To address this, the team introduced a manufacturing‑compatible transfer‑printing approach for seamless monolithic integration of the three emissive layers.
The researchers pinpointed the key degradation route in traditional transfer printing - excessive interfacial adhesion that damages the underlying perovskite - and countered it with a temperature‑triggered “solid–liquid” switchable interface. This interface is formed through a methylamine‑assisted transient liquefaction process, which temporarily softens the receiving layer surface, enabling clean release and self‑healing of the perovskite film once cooled. The result is a damage‑free transfer with minimal interfacial stress and highly uniform optical coupling between layers.
In tandem with this process, the group engineered an interconnecting layer (ICL) featuring embedded dipoles and tunneling‑assisted charge injection. This advanced ICL reduces the voltage drop between sub‑LEDs to just ~0.5 V - comparable to single‑junction operation - while preserving balanced carrier recombination across all three emissive units.
The resulting triple‑junction all‑perovskite white LED achieves a remarkable color gamut of 143% relative to the NTSC standard, a maximum luminance exceeding 67,000 cd m⁻², and a certified external quantum efficiency (EQE) of 16.4%. To underline the practical potential of the approach, the team also built a 2.0 × 2.0 cm² prototype display, demonstrating consistent performance on both rigid glass and flexible polymer substrates.
According to the researchers, this transfer‑printing platform offers a scalable and industry‑ready route for integrating multiple perovskite emissive layers without compromising structural integrity. The method could accelerate the commercialization of monolithic multicolor perovskite LEDs for thin, bright, and color‑accurate display panels.
