Designer Aluminium Precursors for the Inkjet Printing of Electrical Circuits

印刷电子产品正融入现代生活的方方面面，从发光二极管到太阳能电池，再到印刷生物传感器，如可穿戴电子产品。预计到2030年，仅柔性电子产品市场的价值就将达到740亿美元。虽然这种技术已经存在，可以制造大规模的柔性电子产品，通过环保的方式，采用喷墨印刷的卷对卷工业过程，目前所使用的金属油墨有其局限性。熔融金属的图案与可负担得起的柔性材料（包括可再生的环保塑料或纸张）不相容，这种不匹配部分是由于金属的高熔点（通常超过1000度）和一系列塑料，纸张或织物材料的变形温度相当低（约100 - 200摄氏度）。目前用于印刷电子产品生产的技术是耗时和昂贵的多步骤技术，需要使用有毒化学品。这些最先进的技术需要金属薄片/颗粒“熔化”在一起，导致层之间的污染物，从而降低金属的整体导电性。解决这个问题的一个显而易见的办法是使用特殊设计的墨水，这种墨水含有小分子，可以在任何材料上印成任何想要的图案，然后在低温下被热“激活”，从而将它们转化为导电金属。该项目旨在设计和合成新的小分子，以提高现有印刷技术的性能。这将为目前工业上基于银或铜的纳米颗粒油墨提供一种可调的替代品，这些油墨的活化温度太高，无法在许多材料上印刷。此外，了解小分子的结构如何影响其作为金属前体的能力是具有挑战性的，获得洞察力将使我们能够调整热激活温度，从而在打印后可以产生高导电性的金属。铝金属储量丰富，具有与银和铜相当的导电性，但从未在工业上用于喷墨打印导电轨道。这是因为尽管合成铝化学领域丰富，但合适的前体并不存在。为了克服这个问题，我们建议调整我们的小分子设计，以更好地与现代低温沉积技术兼容。为了获得在设备制造中使用印刷技术的好处，将生产在低温下转换的油墨（提供与低成本柔性材料的兼容性）。该项目将创建一个新型高性能铝墨水库，这种墨水可以在空气中印刷和烧结在低成本的柔性材料上，用于集成到电子设备中。该项目的目标是开发新的含铝小分子，将其配制成金属油墨，然后将高导电性金属特征打印到低成本的柔性材料上，用于电子设备。

Printed electronics are becoming integrated into every part of modern-day life, from light-emitting diodes, to solar cells and printed biosensors such as wearable electronics. The flexible electronics market alone is predicted to be valued at $74 billion by 2030. Whilst the technology already exists to manufacture large-scale flexible electronics, by way of the environmentally friendly, roll-to-roll industrial processes which employ inkjet printing, currently the metal inks that are employed have their limitations. The patterning of molten metals is incompatible with affordable flexible materials, including renewable eco-friendly plastics or paper, this mismatch is due to, in part, the high melting point of metals (often over a thousand degrees) and the deformation temperature of a range of plastic, paper or fabric materials being considerably lower (ca. 100 - 200 degrees Celcius). Current techniques 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.An obvious solution to this problem is the use of specially designed inks, containing small molecules that can be printed into any desired pattern onto any material, and then be thermally 'activated' at low temperatures, in order to convert them to conductive metal. This project aims to design and synthesise new small molecules in order to improve the performance of existing printing technologies. These would provide a tuneable alternative to the current industrial nanoparticle inks based on silver or copper whose activation temperatures are too high for printing onto many materials. In addition, understanding how the structure of a small molecule can influence its ability to act as a precursor to the metal is challenging, and gaining insight will enable us to adjust thermal activation temperatures, such that after printing, it can yield highly conductive metal.Aluminium metal is earth abundant, boasts conductivity comparable to silver and copper and yet has never been used industrially to inkjet print conductive tracks. This is because suitable precursors do not exist, despite the rich field of synthetic aluminium chemistry. To overcome this problem, we propose to adapt our small molecule design to be better compatible with modern lower temperature deposition techniques. To reap the benefits of using printing techniques for device fabrication inks that will transform at low temperatures (affording compatibility with low cost flexible materials) will be produced. This project will create a library of novel highly performing inks from aluminium which can be printed and sintered in air on low cost flexible materials for incorporation into electronic devices. The aim of this project is to develop new small molecules containing aluminium, formulate these into metal inks and subsequently print highly conductive metal features onto low cost flexible materials for use in electronic devices.