High-Efficiency Pure-Red Perovskite Quantum-Dot Light-Emitting Diodes

It is still challenging to achieve high-efficiency pure -red (620-650 nm wavelength) perovskite light-emitting diodes (PeLEDs). Herein, we report pure-red PeLEDs with Commission Internationale de l'Eclairage coordinates (0.703, 0.297) meeting the Rec. 2020, an external quantum efficiency of 20.8%, and a luminance of 3775 cd/m2. This design is based on the strong quantum confinement CsPbI3 quantum dots (QDs) capped by composite ligands of 3-phenyl-1-propylamine and tetrabutylammonium iodide. This strategy stabilized the structure of the strong-confined QDs and reduced the influence of the electric field-induced Stark effect on the PeLEDs. Furthermore, the exciton binding energy of the QDs was decreased by the composited ligands to suppress Auger recombi-nation within the devices. Additionally, the valence-band maximum of the QDs was lifted to match the hole-transport layer, thus balancing charge injection in the PeLEDs. Our device also demonstrated a stable electroluminescence spectrum and a lifetime of 5.6 times longer than the control device.

Automated summary

This study presents a solution to achieve high-efficiency pure-red perovskite light-emitting diodes (PeLEDs) by stabilizing the structure of quantum dots and reducing adverse effects. The use of composite ligands helped stabilize the strong-confined quantum dots and suppress Auger recombination in the devices. Additionally, adjustments in the valence band of the quantum dots improved charge injection balance in the PeLEDs.