Ligand-Assisted Direct Photolithography of Perovskite Nanocrystals Encapsulated with Multifunctional Polymer Ligands for Stable, Full-Colored, High-Resolution Displays

Abstract

Micropatterns with a high stability, definition, and resolution are an absolute requirement in advanced display technology. Herein, patternable perovskite nanocrystals (PNCs) with excellent stability were prepared by exchanging pristine ligands with multifunctional polymer ligands, poly­(2-cinnamoyloxyethyl methacrylate). The polymer backbone contains a cinnamoyl group that has been widely employed as a photo-cross-linker under 365 nm UV irradiation. Also, the terminal group is readily adjustable among NH3Cl, NH3Br, and NH3I, allowing us to obtain multicolored PNCs via instant anion exchange. Furthermore, the resulting ligand exchanged PNCs exhibited enhanced stability toward polar solvents without any undesirable influence on the structural or optical properties of the PNCs. Using anion exchanged PNCs, RGB microarrays with a subpixel size of 10 μm × 40 μm were successfully demonstrated. Our results highlight the versatility and feasibility of a simplified patterning strategy for nanomaterials, which can be generally applied in the fabrication of various optoelectronic devices.

Direct optical patterning of perovskite nanocrystals with ligand cross-linkers

“…This high patterning efficiency, originated from the nonspecific nature of nitrene insertion, distinguishes DOPPLCER from methods based on ligands with specific, cross-linkable fragments. The latter typically involve high mass ratio (ligand/NCs over 100%) of long, insulating polymeric ligands ( 29 , 31 ) and high exposure doses ( 31 ). Similar contrast in patterning efficiency of the nonspecific and specific cross-linking mechanism has been observed in the case of polymers ( 34 ).…”

“…This is in stark contrast with previous reports on perovskite NCs with cross-linked ligands via x-ray irradiation or with polymeric ligands containing cross-linkable fragments. In those cases, the dense, cross-linked ligand shells/matrices prevent the transformation of perovskite NCs in the presence of halides or polar environments ( 16 , 29 ). This difference suggests that DOPPLCER uses a small amount of ligands and induces low degree of cross-linking.…”

Surface patterning techniques for proteins on nano- and micro-systems: a modulated aspect in hierarchical structures

“…Photolithography enables the patterning of surfaces that can be further activated for ligand binding. 156 One such approach was applied in the fabrication of photoactivable ligand patterning to identify drug targets and photoaffinity labeling of targeted macromolecules. 157 Furthermore, photolithography assisted in the development of biosensors for the identification and detection of oligonucleotides for gene mutation in breast cancer 158 and determining cell heterogenicity during the tumor stages, 159 while stencil patterning was used for the fabrication of a 3D coculture model for cancer and normal fibroblast micropatterned surfaces.…”

The Contribution of NMR Spectroscopy in Understanding Perovskite Stabilization Phenomena

“…Solution NMR spectroscopy, already largely applied in colloidal NC analysis [ 89 ], contributes to the characterization of PNCs by: (i) checking the purity and the integrity of the product after the purification steps [ 90 , 91 ], (ii) evaluating the stability over time and the effect of the halide [ 23 ], (iii) investigating the capping ligands [ 18 ] and their interactions with the ligands themselves, the lattice and/or the precursors [ 92 , 93 , 94 , 95 , 96 ] and iv) providing insights into ligand exchange [ 97 ] and self-assembly [ 98 ] processes aimed at improving the stability and final device properties.…”