PAPIER - Plasma Assisted Printing of Metal Inks with Enhanced Resistivity

点击翻译按钮获取中文摘要

The move toward low-cost flexible electronics is one of the standout advancements of this century: printed electronics are integrated into every part of modern-day life, from light-emitting diodes, to solar cells and printed biosensors such as wearable electronics. However, as we move toward ever-lower processing temperatures in order to enable printing on paper, polymers or even skin, the technology is struggling to catch up. Thermal deposition techniques have their limitations, and the patterning of molten metals is incompatible with affordable flexible materials, including renewable eco-friendly plastics or paper. This mismatch is due, in part, to the high melting point of metals (often over a thousand degrees) which is in stark contrast to the deformation temperature of a range of plastic, paper or fabric materials (considerably lower approx. 100 - 200 degrees Celsius). Techniques currently used in the production of printed electronics are time-consuming and expensive multi step-techniques that require the use of toxic chemicals. These state-of-the-art techniques require metal flakes/particles to be 'melted' together, resulting in contaminants between layers, which reduce overall conductivity of the metal.The atmospheric-pressure and room-temperature printing of metallic coatings from a simple and scalable method is an unmet need of the ever-growing printed electronics market. With a few exceptions, conductive ink materials are dispersions of metallic nanoparticles. Nevertheless, these inks require sintering at temperatures which limits their widespread use (> 50 degrees celcius). In addition, the nanoparticles often clog inkjet printer nozzles upon coating. Metal-organic decomposition (MOD) inks provide an alternative to nanoparticle inks. The development of this technology could have profound benefits for many different scientific fields. This PAPIER project focusses on organometallic compounds, as opposed to nanoparticles, for use in MOD inks in an atmospheric-pressure plasma assisted printing process. The unique and unprecedented combination of MOD inks with plasma assisted printing will enable intricate patterned metallic surfaces to be produced on a large scale and on a range of substrates at atmospheric pressure and room temperature. Exhaustive surface characterizations will allow a deep understanding of mechanisms involved in the printing of MOD inks and promote the elaboration of other new functional metallic thin films.Typically ink formulations are optimized using mass screening and elimination of failures which means that there are no comprehensive studies dedicated to the fundamental chemistry involved. Consequently, there is an urgent need to explore this area further. The ability of the international collaborators at the LIST to avoid using thermal activation is crucial to the success of this project, highlighting the complementary and synergetic expertise of synthetic excellence and plasma deposition. This project aims to improve the performance of existing printing technologies. These would provide a tuneable alternative to the current industrial methods based on silver whose activation temperatures are too high for printing onto many materials.Both aluminium and copper are low cost, earth abundant, and conduct with as much effectiveness as silver. We will use our small molecules in the plasma printing of metals, which will be compatible with modern lower temperature deposition techniques. To reap the benefits of using printing techniques for device fabrication, inks that will transform at room temperatures (affording compatibility with low cost flexible materials) will be produced. This project will create a library of novel highly performing inks from aluminium and copper which can be printed and sintered in air on low cost flexible materials for incorporation into electronic devices.