Direct optical lithography of functional inorganic nanomaterials

Abstract

Photolithography is an important manufacturing process that relies on using photoresists, typically polymer formulations, that change solubility when illuminated with ultraviolet light. Here, we introduce a general chemical approach for photoresist-free, direct optical lithography of functional inorganic nanomaterials. The patterned materials can be metals, semiconductors, oxides, magnetic, or rare earth compositions. No organic impurities are present in the patterned layers, which helps achieve good electronic and optical properties. The conductivity, carrier mobility, dielectric, and luminescence properties of optically patterned layers are on par with the properties of state-of-the-art solution-processed materials. The ability to directly pattern all-inorganic layers by using a light exposure dose comparable with that of organic photoresists provides an alternate route for thin-film device manufacturing.

Colloid‐Interface‐Assisted Laser Irradiation of Nanocrystals Superlattices to be Scalable Plasmonic Superstructures with Novel Activities

“…With the achievements of chemical synthesis of the monodisperse colloidal nanocrystals (NCs) over the past 2 decades, the bottom‐up self‐assembly strategies of such NCs to be multifunctional superstructures at bulk scale are critical for their electronic and optoelectronic devices applications. Such strategies include the interface‐assisted assemble superlattices (SLs), DNA‐based sequence‐specific bonding assemble structures, direct NC pattern optical lithography by photochemically active cation/anion groups, self‐assemblies by NC micelle to diamond‐like supercrystals, and so on . In as‐formed NC assembly SLs, the coupling interactions of constituent NCs are usually limited in the application of film‐scale devices as a result of the interparticle spacing produced by long‐chain organic ligands .…”

“…Such strategies include the interfaceassisted assemble superlattices (SLs), DNA-based sequence-specific bonding assemble structures, direct NC pattern optical lithography by photochemically active cation/anion groups, self-assemblies by NC micelle to diamond-like supercrystals, and so on. [1][2][3][4][5][6][7][8][9][10] In as-formed NC assembly SLs, the coupling interactions of constituent NCs are usually limited in the application of film-scale devices as a result of the interparticle spacing produced by long-chain organic ligands. [11][12][13][14] For example, such insulating ligands at building block surfaces can generate a barrier for the electronic transport.…”

Direct Imprinting of Quasi‐3D Nanophotonic Structures into Colloidal Quantum‐Dot Devices

“…Therefore, 3D nanopatterning of CQDs requires the development of orthogonal processes that do not detrimentally alter their surface chemistry. With surface passivation or photoresist‐free lithographic techniques, micrometer‐scale 2D patterns of CQDs have been demonstrated. However, high‐resolution direct fabrication of subwavelength 3D structures on CQDs is still technically challenging.…”

“…Therefore, 3D nanopatterning of CQDs requires the development of orthogonal processes that do not detrimentally alter their surface chemistry. With surface passivation [15] or photoresist-free lithographic techniques, [16] micrometer-scale 2D patterns of CQDs have been demonstrated. However, high-resolution direct fabrication of subwavelength 3D structures on CQDs is still technically challenging.Prior attempts to nanostructure CQDs include molding of soft interfacial carrier transport layers, [17] transfer printing, [18,19] and template-assisted deposition [20][21][22] of CQD solutions, as well as incorporating CQD into poly(methyl methacrylate) [23,24] or UV-curable resins [25] that can be molded under heat and pressure.…”

A Building Brick Principle to Create Transparent Composite Films with Multicolor Emission and Self‐Healing Function

“…[10] Currently, QD pixels in prototype display devices are mostly realized by monolithic microfabrication relying on multilayer photolithography [11] to define each color plane. [12] Alternative fabrications methods utilize inkjet printing [13] and transfer printing [2,14] to add fluorophores after the lithography stage, but have severe disadvantages such as introducing inhomogeneities during drying, [15] leading to contamination of different colors. Fabricating largescale and uniform composite polymer/QD films and assembling them into pixels afterward in a kind of "top-down" process may help to tackle the challenges encountered in the fabrication processes mentioned above.…”