Efficient and Bright Deep-Red Light-Emitting Diodes based on a Lateral 0D/3D Perovskite Heterostructure

Bright and efficient deep-red light-emitting diodes (LEDs) are important for applications in medical therapy and biological imaging due to the high penetration of deep-red photons into human tissues. Metal-halide perovskites have potential to achieve bright and efficient electroluminescence due to their favorable optoelectronic properties. However, efficient and bright perovskite-based deep-red LEDs have not been achieved yet, due to either Auger recombination in low-dimensional perovskites or trap-assisted nonradiative recombination in 3D perovskites. Here, a lateral Cs4PbI6/FA(x)Cs(1-)(x)PbI(3) (0D/3D) heterostructure that can enable efficient deep-red perovskite LEDs at very high brightness is demonstrated. The Cs4PbI6 can facilitate the growth of low-defect FA(x)Cs(1-)(x)PbI(3), and act as low-refractive-index grids, which can simultaneously reduce nonradiative recombination and enhance light extraction. This device reaches a peak external quantum efficiency of 21.0% at a photon flux of 1.75 x 10(21) m(-2) s(-1), which is almost two orders of magnitude higher than that of reported high-efficiency deep-red perovskite LEDs. Theses LEDs are suitable for pulse oximeters, showing an error <2% of blood oxygen saturation compared with commercial oximeters.

Automated summary

Bright and efficient deep-red LEDs are crucial for medical therapy and biological imaging. However, achieving high brightness deep-red perovskite-based LEDs has been a challenge. This study demonstrates a lateral Cs4PbI6/FA(x)Cs(1-)(x)PbI(3) (0D/3D) heterostructure that enables highly efficient deep-red perovskite LEDs. These LEDs exhibit a peak external quantum efficiency of 21.0% at a significantly higher photon flux than previously reported.