Inkjet-Printed Salt-Encapsulated Quantum Dot Film for UV-Based RGB Color-Converted Micro-Light Emitting Diode Displays

A promising method has been demonstrated to fabricate quantum dot (QD)-converted full-color micro-light emitting diodes (LEDs) by inkjet printing (IJP) instead of the mass transfer of three red-green-blue (RGB) color chips. By introducing an additional medium, that is, NaCl into a formulated ink, QD deposition is manipulated by the NaCl-QD adhesive force and the capillary flow inside the liquid drop via varying the substrate hydrophobicity, which enabled spontaneous self-encapsulation of QDs in a single NaCl crystal. An RGB QD@NaCl array with a small pixel size and uniform size distribution (diameter = 3.74 ± 0.5 μm) is obtained in the IJP process, which demonstrated a full-color micro-LED display with a color gamut of approximately 110% of the National Television System Committee (NTSC) standard.