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This Minireview compares two distinct ink types, namely metal‐organic decomposition (MOD) and nanoparticle (NP) formulations, for use in the printing of some of the most conductive elements: silver, copper and aluminium. Printing of highly conductive features has found purpose across a broad array of electronics and as processing times and temperatures reduce, the avenues of application expand to low‐cost flexible substrates, materials for wearable devices and beyond. Printing techniques such as screen, aerosol jet and inkjet printing are scalable, solution‐based processes that historically have employed NP formulations to achieve low resistivity coatings printed at high resolution. Since the turn of the century, the rise in MOD inks has vastly extended the range of potentially applicable compounds that can be printed, whilst simultaneously addressing shelf life and sintering issues. A brief introduction to the field and requirements of an ink will be presented followed by a detailed discussion of a wide array of synthetic routes to both MOD and NP inks. Unindustrialized materials will be discussed, with the challenges and outlook considered for the market leaders: silver and copper, in comparison with the emerging field of aluminium inks. [ABSTRACT FROM AUTHOR]

The developments in inkjet printing technology and the printed electronics industry in the past two decades have provided cost-effective, environmentfriendly, and reliable alternates to traditional methods of fabricating electrical devices. However, most commercial metallic inks require high sintering temperatures to form desired functional patterns, which limits the applications of printed electronics in scenarios that require electrical devices on thermally sensitive substrates, like biomaterials or bio-synthetic composite materials. This study provides the synthetic route of a novel silver-based metal organic decomposition (MOD) ink which is used to form highly conductive silver films on the thermally sensitive skin-inspired silk/epoxy composite substrates by directly inkjet printing with accurate pattern control, whilst self-decomposing and sintering at room temperature. The fabricated silver patterns on the thermally sensitive silk/epoxy composite substrate are highly conductive with conductivity of 4.65 × 104 S m-1. These silver patterns also show impressive malleability as bulk silver films, which can be further developed into motion sensors for wearable devices or medical applications. Our strategy provides a general platform for electronic functionalization without temperature constraints. The particle-free, reactive silver-precursor, and lower sintering temperature of the ink also widen the choices of substrates, as exemplified herein with outstanding printing quality and high electrical conductivity (1.20 × 106 S m-1) also achieve on paper. [ABSTRACT FROM AUTHOR]

The field of printed electronics strives for lower processing temperatures to move toward flexible substrates that have vast potential: from wearable medical devices to animal tagging. Typically, ink formulations are optimized using mass screening and elimination of failures; as such, there are no comprehensive studies on the fundamental chemistry at play. Herein, findings which describe the steric link to decomposition profile: combining density functional theory, crystallography, thermal decomposition, mass spectrometry, and inkjet printing, are reported. Through the reaction of copper(II) formate with excess alkanolamines of varying steric bulk, tris‐co‐ordinated copper precursor ions: "[CuL3]," each with a formate counter‐ion (1–3) are isolated and their thermal decomposition mass spectrometry profiles are collected to assess their suitability for use in inks (I1–3). Spin coating and inkjet printing of I1,2 provides an easily up‐scalable method toward the deposition of highly conductive copper device interconnects (ρ = 4.7–5.3 × 10−7 Ω m; ≈30% bulk) onto paper and polyimide substrates and forms functioning circuits that can power light‐emitting diodes. The connection among ligand bulk, coordination number, and improved decomposition profile supports fundamental understanding which will direct future design. [ABSTRACT FROM AUTHOR]

Although nanoparticle (NP) inks are well known, the rise in metal-organic decomposition (MOD) inks has extended the range of compounds that can be printed, whilst simultaneously addressing shelf life and sintering issues. Conductivity, inks, nanoparticle, precursor, printing Keywords: conductivity; inks; nanoparticle; precursor; printing EN conductivity inks nanoparticle precursor printing 1 1 1 06/05/21 20210601 NES 210601 B Printing of highly conductive b features has found purpose across a broad array of electronics and as processing times and temperatures reduce, the avenues of application expand to low-cost flexible substrates, materials for wearable devices and beyond. [Extracted from the article]