Exceptional Light Sensitivity by Thiol–Ene Click Lithography

Abstract

Lithographic patterning, which utilizes the solubility switch of photoresists to convert optical signals into nanostructures on the substrate, is the primary top-down approach for nanoscale fabrication. However, the low light/electron-energy conversion efficiency severely limits the throughput of lithography. Thiol–ene reaction, as a photoinitiated radical addition reaction, is widely known as click reaction in the field of chemistry due to its extremely high efficiency. Here, we introduce a click lithography strategy utilizing the rapid thiol–ene click reaction to realize ultraefficient nanofabrication. This novel approach facilitated by the implementation of ultrahigh-functionality material designs enables high-contrast patterning of metal-containing nanoclusters under an extremely low deep-ultraviolet exposure dose, e.g., 7.5 mJ cm–2, which is 10–20 times lower than the dose used in the photoacid generator-based photoresist system. Meanwhile, 45 nm dense patterns were also achieved at a low dose using electron beam lithography, revealing the great potential of this approach in high-resolution patterning. Our results demonstrated the high-sensitivity and high-resolution features of click lithography, providing inspiration for future lithography design.

Direct photocatalytic patterning of colloidal emissive nanomaterials

“…In direct optical lithography, patterns are formed by photoinduced chemical reactions of photosensitive ligands or additives, which result in a solubility change of nanomaterials [e.g., metal oxide (16), PeNCs (17), and QDs (12)] at light-exposed regions without the need for a polymeric photoresist. Various photosensitive motifs and photochemical reactions such as azide (17)(18)(19)(20)(21), benzophenone (22), cinnamoyl (23), photo-acid generation (12), oxime sulfonate (13), thiol-ene (24)(25)(26)(27), photo-amine generation (28), oxide bridging (16), photo-oxidation (29), and alkene cross-linking (30) have been explored for direct optical patterning of colloidal emissive nanocrystals. However, the lithography process often induces substantial surface damage to the deposited emissive nanomaterials, thereby degrading their optical properties such as PLQY (13,17).…”

Introduction of Photopolymerization Technology and Application

“…[70] Liu et al [1] Figure 19 Structures of the oxime ester PIs, mercaptan and monomers used in the photopolymerization. [1] He et al, [79] designed a novel click lithography strategy based on the rapid thiol-ene click reaction to realize ultraefficient nanofabrication, the schematic illustration of thiol-ene reaction and click lithography are displayed in Figure 20. First of all, this work prepared a multialkene-functionalized zirconium (Zr)-containing MOC with a molecular size of 1.6 nm, and the material exhibits ultrahigh alkene density and extremely small component size, which is conducive to achieving high sensitivity and high resolution of the thiol-ene reaction.…”

“…(c) Resist film composed of ZrO2-MAA MOCs and thiol compounds. (d) Crosslinked and non-crosslinked structures formed by radiation-induced thiol-ene click reaction [79].…”

Enhancing energy transfer through visible-light-driven polymerization in a metal–organic framework

“…As a result, for effective photosensitive materials, it is especially important to place properly ordered photoactive groups. [7][8][9] In contrast to the defects in conventional photosensitive materials such as inorganic composites and organic polymers, metal-organic frameworks (MOFs) might be ideal substrates for novel arrays of highly ordered photoresponsive groups due to their intrinsic structural characteristics and wide functional tailorability. [10][11][12] To date, various strategies and approaches have been developed to integrate photoresponsive groups into the lattice, thereby imparting novel photosensitive properties to MOFs, such as the photodimerization of anthracene guests.…”