Junho Kim1,Jung-Yong Lee1
Korea Advanced Institute of Science and Technology1
Junho Kim1,Jung-Yong Lee1
Korea Advanced Institute of Science and Technology1
Perovskite quantum dots (PeQDs) are promising material for next-generation display owing to their superior optoelectronic properties. However, the multi-color patterning of PeQDs remains fundamental challenging because the PeQDs are very vulnerable for conventional patterning process containing direct exposure of ultra-violet (UV) ray, electron-beam (E-beam), or polar solvents used as developer. Furthermore, the shorter ligand exchange and halide anion exchange are required to use the PeQDs as active materials and express various emitting-light colors easily in PeQD LED devices.<br/>In this study, we propose a novel all-in-one process simultaneously exchanging ligands and halide anions in film-state for enhancing the LED performance, converting emitting-light color, and patterning of cesium lead halide PeQD LEDs for full-color display.<sup>[1]</sup> The proposed all-in-one process significantly enhanced the performances of PeQD LEDs by passivating the PeQDs with shorter ligands. The dense passivation with shorter ligands also enhanced the chemical stability of PeQDs. In addition, we fabricated red (R), green (G), and blue (B) LEDs with extremely narrow emission spectra using cesium lead bromide PeQDs and appropriate butylammonium halide solution. Furthermore, the proposed all-in-one process in film-state facilitated rapid color change in localized areas, thereby aiding in realizing fine patterns of narrow widths (300 µm) using simple contact masks. Consequently, the all-in-one process made it possible to from the multi-color patterning without direct exposure of UV ray, E-beam, and developer to PeQD films. Finally, we can fabricate various R/G/B multi-color patterning electroluminescence (EL) LED devices such as R/G/B pixels in a substrate, one pixel containing R/G/B colors between a pair of electrodes, and word-patterned (“KAIST”) LEDs, using the all-in-one process.<br/><br/>[1] J. Kim, K.-W. Seo, S. Lee, K. Kim, C. Kim, and J.-Y. Lee, <b><i>Adv. Sci.</i></b>, 2022, 9, 2200073.