Print‐Light‐Synthesis of Platinum Nanostructured Indium‐Tin‐Oxide Electrodes for Energy Research

Abstract

Print‐light‐synthesis is a new concept for the large‐scale in situ fabrication of nanoparticles and structures on large substrates. Here, Pt nanoparticles are synthesized on indium tin oxide (ITO) coated glass slides by using combined inkjet printing and photonic curing operated under ambient conditions and with low material usage. A formulated chloroplatinic acid based ink provides stable and reproducible jetting, optimized ink–substrate interaction and fast ink drying to create well‐defined thin precursor films acting as nanoreactors. The precursor loading is precisely controlled by the printing parameters. Then, a short light pulse from a Xe flash lamp fully converts the printed Pt precursor containing film into pure Pt nanoparticles. The optimum precursor coverage is ≈1 µg mm−2 Pt consuming as less as ≈50 nL mm−2 of ink. Neither reducing nor capping agents are used resulting in pure Pt nanoparticles (30 nm average size) and micrometer‐size aggregates. The nanostructures are well‐adhered to the ITO substrate and show a stable electrochemical performance for the oxygen reduction reaction. The fast and cost‐effective process optimization in terms of ink formulation, substrate pre‐treatment, inkjet printing resolution, and post‐processing for the rapid fabrication of Pt nano‐ and microparticle‐coated ITO electrodes is presented and discussed.

Oxidative Print Light Synthesis Thin Film Deposition of Prussian Blue

“…Sustainable technologies for the low-cost and large-scale manufacturing of devices based on nanomaterials have been proposed for different applications, from biosensors to energy conversion devices . In the field of additive manufacturing, substantial effort has been devoted to inkjet printing (IJP), which is a rapidly developing technique with relatively low cost and flexibility for depositing a large group of nanomaterials − on a virtually unlimited range of substrates, with minimal waste of reactants. − IJP can be tuned to deposit thin films or patterns with homogeneous and controlled thickness, design area, material composition, and loading. These patterns can be adjusted to requirements by the control of droplet interpolation and number of layers.…”

“…Moreover, IJP can be employed as a manufacturing tool from a single prototype to large-scale fabrication, as observed in different industrial processes . However, for reproducible and stable printing of materials, inks must satisfy certain physical requirements in terms of surface tension and viscosity to provide the formation of droplets and stable jetting. − , After the printing process, especially for electrochemical applications, the printed material/precursor must be sintered to obtain the desired functionality of the printed pattern. This step is usually performed by conventional thermal sintering in a furnace and recently by UV lamps for polymerization and white-light sintering .…”

“…In a few milliseconds, light absorption will promote the heating of the printed thin film precursor (several hundred degrees centigrade) and cause material thermal transformation, for example, sintering. Because it is nonthermal equilibrium, the advantage of this methodology stems from the notion that the heat produced in the film does not cause the degradation of some common substrates (e.g., poly­(ethylene terephthalate) (PET) and ITO glass). ,, Because the thermal mass of the substrates is several orders of magnitude larger than that of the thin film, the heat that is generated is attenuated. Thus, the thermal penetration depth is too short, and the substrates do not suffer from the high surface temperatures, , which enables the in situ sintering of materials on thermally sensitive substrates .…”

“…Because it is nonthermal equilibrium, the advantage of this methodology stems from the notion that the heat produced in the film does not cause the degradation of some common substrates (e.g., poly­(ethylene terephthalate) (PET) and ITO glass). ,, Because the thermal mass of the substrates is several orders of magnitude larger than that of the thin film, the heat that is generated is attenuated. Thus, the thermal penetration depth is too short, and the substrates do not suffer from the high surface temperatures, , which enables the in situ sintering of materials on thermally sensitive substrates . As a result, the coupling of inkjet printing and white-light sintering provides a new concept/methodology known as print light synthesis (PLS), which is a fast and reproducible protocol that enables in situ fabrication of nanomaterials on thermally sensitive substrates (e.g., polymers) .…”

“…Thus, the thermal penetration depth is too short, and the substrates do not suffer from the high surface temperatures, , which enables the in situ sintering of materials on thermally sensitive substrates . As a result, the coupling of inkjet printing and white-light sintering provides a new concept/methodology known as print light synthesis (PLS), which is a fast and reproducible protocol that enables in situ fabrication of nanomaterials on thermally sensitive substrates (e.g., polymers) . Considerable efforts have been made to develop printed materials for applications in energy storage devices, for example, for Li ion batteries (LIBs). ,,, Here, we explore new methods for the production of alkali ion batteries.…”