Laser digital patterning of conductive electrodes using metal oxide nanomaterials

Abstract

As an alternative approach to the conventional deposition and photolithographic processes, the laser digital patterning (LDP) process, which is also known as the laser direct writing process, has attracted considerable attention because it is a non-photolithographic, non-vacuum, on-demand, and cost-effective electrode fabrication route that can be applied to various substrates, including heat-sensitive flexible substrates. The LDP process was initially developed using noble metal nanoparticles (NPs) such as Au and Ag because such materials are free from oxidation even in a nanosize configuration. Thus, the NPs must be fused together to form continuous conductive structures upon laser irradiation. However, common metals are easily oxidized at the nanoscale and exist in oxidized forms owing to the extremely large surface-to-volume ratio of NPs. Therefore, to fabricate conductive electrodes using common metal NPs via the LDP process, laser irradiation should be used to sinter the NPs and simultaneously induce additional photochemical reactions, such as reduction, and defect structure modification to increase the conductivity of the electrodes. This review summarizes recent studies on the LDP process in which metal oxide NPs, such as ITO, ZnO, CuO, and NiO, were exclusively utilized for fabricating conductive electrodes. The outlook of the LDP process for these materials is also discussed as a method that can be used together with or as a replacement for conventional ones to produce next-generation transparent conductors, sensors, and electronics.

Scalable and High-Throughput Top-Down Manufacturing of Optical Metasurfaces

“…Laser-based manufacturing techniques have provided the required technological and cost-effective aspects to produce micro-and nanostructures using top-down approaches [75][76][77]. One technique of fabricating periodic structures is LIL [78][79][80][81].…”

Tunable Metasurfaces: The Path to Fully Active Nanophotonics

“…TCOs are available with a range of different properties. [ 123–126 ] In one particular example of using TCOs for the continuous electrical tuning of metasurfaces, Ge surrounded by Al‐doped ZnO (AZO) was used to produce a reflectance difference of over 40% with gate biases from +4 to −4 V while also displaying a large phase modulation up to 270°. [ 127 ] The devices were modeled using an effective medium theory to calculate the phase shifts.…”

Recent Advances in Fabrication of Flexible, Thermochromic Vanadium Dioxide Films for Smart Windows

“…The solution mixture was cast on PET substrates using a stainless-steel coating bar to fabricate large-area, flexible VO 2 (M) films (Figure 12c). The T c of the flexible VO 2 (M) films could be systematically modulated by approximately 24.52 • C for 1 at% of W doping, and the mid-infrared transmission could be modulated by 31% at a T c of 37.3 • C. Inkjet printing has also been widely utilized as a useful direct-write technology to fabricate high-resolution, low-cost, large-area, and uniformsurface films on flexible substrates [141,142]. Haining et al reported the fabrication of VO 2 (M) smart windows via inkjet printing using hydrothermally synthesized VO 2 (M) NPs [143,144].…”