Electrohydrodynamic inkjet printing of perovskite quantum dots for color-conversion micro-LED displays

Abstract Electrohydrodynamic (EHD) inkjet printing has emerged as a powerful micro-/nanofabrication technique for high-resolution perovskite quantum dot (PeQD) color-conversion layers, offering precise control over pixel morphology, dimensions, and composition. This review systematically examines the mechanisms of cone-jet and electrostatic-attraction modes in EHD printing, highlighting recent advances in PeQD ink design, solvent and ligand engineering, and printing parameter optimization. Perovskite precursor and colloidal inks are discussed in detail, emphasizing strategies to enhance droplet ejection stability, suppress coffee-ring effects, and achieve uniform, high-luminescence pixels. Ligand exchange, dual-ligand passivation, and core−shell or polymer encapsulation are shown to effectively mitigate ion migration, surface defects, and environmental degradation, thereby improving photoluminescence efficiency and stability. Multi-channel and multi-nozzle EHD printing systems enable dynamic halide composition control and parallel RGB pixel deposition, facilitating ultrahigh-resolution patterning down to submicron feature sizes. Finally, the review highlights future directions, including synergistic PeQD material synthesis, advanced ink formulation, scalable high-throughput printing, and integration of PeQD color-conversion pixels into full-color micro-LED displays with minimal crosstalk and robust operational stability. These developments collectively demonstrate the immense potential of EHD inkjet printing for next-generation high-performance display technologies.