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Highlights: This article reviews the recent progress in the patterning techniques of metal halide perovskites for full-color displays. Patterning techniques of perovskites are subdivided into in situ crystallization and patterning of colloidal perovskite nanocrystals, including photolithography, inkjet printing, thermal evaporation, laser ablation, transfer printing, and so on. The strength and weakness of each patterning methods are discussed in detail from the viewpoint of their applications in full-color displays. Metal halide perovskites have emerged as promising light-emitting materials for next-generation displays owing to their remarkable material characteristics including broad color tunability, pure color emission with remarkably narrow bandwidths, high quantum yield, and solution processability. Despite recent advances have pushed the luminance efficiency of monochromic perovskite light-emitting diodes (PeLEDs) to their theoretical limits, their current fabrication using the spin-coating process poses limitations for fabrication of full-color displays. To integrate PeLEDs into full-color display panels, it is crucial to pattern red–green–blue (RGB) perovskite pixels, while mitigating issues such as cross-contamination and reductions in luminous efficiency. Herein, we present state-of-the-art patterning technologies for the development of full-color PeLEDs. First, we highlight recent advances in the development of efficient PeLEDs. Second, we discuss various patterning techniques of MPHs (i.e., photolithography, inkjet printing, electron beam lithography and laser-assisted lithography, electrohydrodynamic jet printing, thermal evaporation, and transfer printing) for fabrication of RGB pixelated displays. These patterning techniques can be classified into two distinct approaches: in situ crystallization patterning using perovskite precursors and patterning of colloidal perovskite nanocrystals. This review highlights advancements and limitations in patterning techniques for PeLEDs, paving the way for integrating PeLEDs into full-color panels. [ABSTRACT FROM AUTHOR]

Multifunctional displays, which have various functions in single-device systems without external circuits, are actively investigated as future human-machine interfaces owing to performability of unprecedented functions in compact design. However, their application is limited to visualize the mechanical/electrical signals in light. Herein, stretchable high-resolution multicolor synesthesia display, which can generate synchronized sound and light as input/output sources, is presented by transfer-printing. Transfer-printed emissive composite leads to display with enhanced optical performance and fine sound pressure level. Owing to inherent stretchability of the device, the synesthesia display can stably operate under static and dynamic deformation without distortion in sound relative to the input waveform. User-interactive synesthesia displays are demonstrated for visual -- acoustic encryption, which facilitate advanced encryption, as well as multiplex quick response code that bridges multiple domains with a single device. This approach provides new directions for multifunctional displays, with potential applications in reinforced authentication. [ABSTRACT FROM AUTHOR]

High-resolution semiconductor nanocrystal quantum dot (QD) patterns are required for applications in display devices. For this, the dry transfer printing of QDs is promising because it does not degrade the inherent properties of QDs. However, the effect of the surface ligands on this process remains poorly understood, despite its importance. Herein, we investigate the effect of the surface ligands on the intaglio transfer printing process. Colloidal QDs with organic (C8–C18) or inorganic (I−) ligands are prepared. In various pattern-printing tests, including patterns with a sub-10-μm width, the patterning yield is ∼100% for QDs with long-chain ligands (C18). However, the patterning yield decreases with decrease in the chain length for the organic-ligand-passivated QDs and is the lowest for the QDs passivated with I−. Using surface energy characterization and finite element method simulations, we suggest two printing failure mechanisms: (i) Inorganic-ligand-passivated QDs are not effectively picked-up by the stamp because of poor adhesion, and, (ii) for the organic-ligand-passivated QDs, internal crack formation is easier for QDs having short-chain ligands because of the weak interparticle attraction between QDs. Our findings reveal previously unknown defects of the intaglio printing process and provide guidance for mitigating these problems for preparing high-resolution QD patterns. [Display omitted] • The effect of the surface ligands on the intaglio transfer printing process is investigated. • The patterning yield increases with increase in the chain length of surface ligands, reaching ∼100% with oleic acid-passivated quantum dots even for the sub-10 μm resolution. • Inorganic-ligand-passivated quantum dots are not effectively picked-up by the stamp because of their poor surface adhesion. • For organic-ligand-passivated quantum dots, internal crack formation is easier for quantum dots having short-chain organics because of the weak interparticle attraction. [ABSTRACT FROM AUTHOR]