Recent Advances in Patterning Strategies for Full-Color Perovskite Light-Emitting Diodes

Abstract

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.

Experimental Observation of the Fully Ferroelectric–Fully Ferroelastic Effect in Multiferroic Hybrid Perovskites

“…48 The C−N heads of organic cations are embedded into the open cavities in the inorganic skeleton through hydrogen bonding interaction (Figure S3). The bond lengths between Pb and Cl atoms are varied from 2.845 (4) to 2.910 (4) Å, and the range of bond angles is from 85.37 (11) to 176.48 (13)°. Organic cations as "spacers" are neatly arranged between two adjacent infinite 2D inorganic frameworks composed of corner-shared distorted [PbCl 6 ] octahedral units.…”

“…Multiferroic was initially coined by Aizu in 1968 with the theoretical identification of 42 species of simultaneously ferroelectric and ferroelastic phase transition . The famous inorganic Gd 2 (MoO 4 ) 3 with the fully ferroelectric–fully ferroelastic effect was predicted and successfully validated in 1968, serving as a typical model for fully multiferroic over subsequent decades. , The characteristic of a type of ferroelectric–ferroelastic crystal is that the concurrent alteration of the polarization vector alongside changes in the strain tensor, and vice versa, is fully ferroelectric and fully ferroelastic. − Capitalizing on these dual ferroic effects, the development of high-precision electronic micropositioners, tunable radio frequency filters, compatible grating devices, and adaptive devices has become feasible. − Furthermore, the synergy between ferroelectricity and ferroelasticity can markedly enhance material physical properties. , For example, You et al reported a hybrid perovskite multiferroic [Me 3 NCH 2 Cl]­CdCl 3 , whose illustrious electromechanical conversion performance has been proven to be closely related to the partial coupling of ferroelectricity and ferroelasticity. , Benefiting from the numerous advantages of intimate interplay between full ferroelectricity and full ferroelasticity, recently, a large amount of studies have focused on exploring multiferroic materials with ferroelectricity and ferroelasticity. − However, constructing ferroelectric that is compatible with ferroelasticity has been a great challenge due to the strict requirements of crystallographic symmetry, reasonable symmetry breaking, and ingenious evolution of lattice parameters. − …”

Ion Migration in Metal Halide Perovskites: Characterization Protocols and Physicochemical Mechanisms

“…Metal halide perovskites (MHPs) have been the subject of considerable academic interest over the past decade, due to their exceptional photoelectric properties, including the high light-absorption coefficient, long diffusion length of charge carriers, and tunable optical bandgap, which make them promising as the active media for a range of high-efficiency photoelectric devices, such as solar cells, light-emitting diodes, and photodetectors. − MHP is typically formulated as ABX 3 , where A, B, and X represent monovalent cation, bivalent metal cation, and halide anion, respectively . Given the intrinsically low formation energy of structural distortion, MHPs generally suffer from soft lattice and deformable structures .…”