The Synthesis and Characterization of the Highly Stable Perovskite Nano Crystals and Their Application to Ink-jet Printed Color Conversion Layers

Abstract

The green perovskite(CsPbBr3, FAPbBr3) and red perovskite(CsPbBr1I2) colloidal nanocrystals were synthesized by proper synthetic methods for the wide color gamut low-cost displays. The prepared perovskite colloidal nanocrystal solutions were formulated into the ink-jet printable homogeneous inks and uniformly coated as the color conversion layers of the quantum dot organic light emitting diode displays. The silica capped CsPbBr3 nanocrystals were very stable in high temperature observation while the FAPbBr3 showed the excellent long-term stability at room temperature even without the silica passivation. The red perovskite (CsPbBr1I2 CNCs) also showed enhanced long-term stability by removing excess unreacted precursors and ligands through the purification. The ink-jet printed color conversion films had very narrow full-width-at-half-maximums of around 20 nm and high photoluminescence quantum yields of 76.9 % for green and 73.1 % for red, respectively. Particularly, the FAPbBr3 thin film had an excellent cut-off ratio of blue emission and exhibited external quantum efficiency of 5.39 % when fabricated as the hybrid display devices.