Fabrication of Perovskite Nanocrystal Light-Emitting Diodes via Inkjet Printing with High-Temperature Annealing

Metal halide perovskite nanocrystals (NCs) have been considered promising materials for applications in light-emitting diodes (LEDs) because of their excellent optoelectronic properties. Inkjet printing is a promising solution-processed technique for perovskite NC LEDs because of the possibilities of using drop on-demand printing with efficient ink utilization. However, perovskite NCs are thermally unstable, which can cause irreversible phase transitions and optical quenching under high-temperature annealing conditions. Here, we demonstrate an inkjet-printed CsPbBr3 NC film for the fabrication of LEDs using high-boiling decalin and octane mixed solvents. The inkjet-printed CsPbBr3 NC film exhibited a high photoluminescence quantum yield (PLQY) of 61.8% and retained its crystal structure even after high-temperature annealing at 200 degrees C, whereas the spin-coated CsPbBr3 NC films showed a decrease in PLQY from 67.3% to 30.6%. The inkjet-printed CsPbBr3 NC LED with a bank-free structure and large-area coating process exhibited a maximum luminance of 1890 cd m-2 and a peak external quantum efficiency of 5.9%, which is a 6-fold higher efficiency than those of spin-coated CsPbBr3 NC LEDs with a high-temperature annealing process.