High-Efficiency and Emission-Tunable Inorganic Blue Perovskite Light-Emitting Diodes Based on Vacuum Deposition

The fabrication of perovskite light-emitting diodes (PeLEDs) with vacuum deposition shows great potential and commercial value in realizing large-area display panel manufacturing. However, the electroluminescence (EL) performance of vacuum-deposited PeLEDs still lags behind the counterparts fabricated by solution process, especially in the field of blue PeLEDs. Here, the fabrication of high-quality CsPbBr3-xClx film through tri-source co-evaporation is reported to achieve high photoluminescence quantum yield (PLQY). Compared with the conventional traditional dual-source co-evaporation, the tri-source co-evaporation method allows for freely adjustable elemental ratios, enabling the introduction of the lattice-matched Cs4Pb(Br/Cl)6 phase with the quantum-limited effect into the inorganic CsPb(Br/Cl)3 emitter. By adjusting the phase distribution, the surface defects of the emitter can be effectively reduced, leading to better blue emission and film quality. Further, the effects of Cs/Pb ratio and Br/Cl ratio on the PLQY and carrier recombination dynamics of perovskite films are investigated. By optimizing the deposition rate of each precursor source, spectrally stable blue PeLEDs are achieved with tunable emission ranging from 468 to 488 nm. Particularly, the PeLEDs with an EL peak at 488 nm show an external quantum efficiency (EQE) of 4.56%, which is the highest EQE value for mixed-halide PeLEDs fabricated by vacuum deposition. This study achieves a series of high efficiency blue perovskite light-emitting diodes (PeLEDs) with tunable emission ranging from 468 to 488 nm by introducing a novel precursor source into the conventional dual-source co-evaporation system. An optimal device with electroluminescence (EL) peak located at 488 nm obtains an external quantum efficiency (EQE) of 4.56%, which paves the way for vacuum-deposited mixed-halide PeLEDs.image

Automated summary

This study demonstrates the fabrication of high-efficiency blue perovskite light-emitting diodes (PeLEDs) with tunable emission ranging from 468 to 488 nm. By introducing a novel precursor source into the conventional dual-source co-evaporation system, CsPbBr3-xClx films with high photoluminescence quantum yield (PLQY) are achieved. The PeLEDs with an EL peak at 488 nm exhibit an external quantum efficiency (EQE) of 4.56%, the highest among vacuum-deposited mixed-halide PeLEDs.