Low-Temperature Annealing of Inkjet-Printed CsPbBr₃ Perovskite Nanocrystal Film for Light-Emitting Diodes

Abstract

Inkjet printing holds promise for fabricating perovskite nanocrystal (NC) light-emitting diodes (LEDs) by enabling on-demand pattern formation with a colloidal ink. However, this method typically requires high-boiling solvents, necessitating higher annealing temperatures compared to conventional spin-coating processes. In this study, we successfully reduced the annealing temperature of inkjet-printed CsPbBr 3 perovskite NC films from 200 to 140 °C by removing the reaction solvent, 1-octadecene (boiling point 315 °C), via a reprecipitation purification process. Annealing the inkjet-printed films at 140 °C under nitrogen conditions in a glovebox suppressed optical quenching by the hole injection layer poly(3,4-ethylenedioxythiophene):poly-(styrene-sulfonate) (PEDOT:PSS), whereas strong optical quenching occurred during annealing at 140 °C under atmospheric conditions. The inkjet-printed CsPbBr 3 NC-LED exhibited a luminance of 944 cd/m 2 and an external quantum efficiency of 4.7% following low-temperature annealing of the CsPbBr 3 NC film under nitrogen conditions. There findings suggest that low annealing temperatures facilitate the formation of a multilayer structure without optical quenching, thus enhancing LED efficiencies.