Inkjet‐Printed Conductive ITO Patterns for Transparent Security Systems

Abstract

Indium tin oxide (ITO) is a transparent conducting material that is widely used in devices where high transparency of the electrodes is required, such as flat panel and liquid crystal displays, touch panels, smart windows, and many others. ITO layers are deposited on a large scale by magnetron sputtering and then structured by lithography to define desired patterns of transparent electrodes. Here, a method for direct printing of transparent conductive patterns from ITO nanoparticle ink is communicated. The method combines inkjet printing with fast flash lamp annealing whereby the main novelty is to use an additional layer of a colored organic dye onto printed ITO to increase light absorption. The dye coating is instantly heated together with the underlying ITO layer by a light pulse, leading to an instant rise of the surface temperature, which is translated into improved optoelectronic properties of the ITO layers. Inkjet‐printed ITO patterns processed with the dye‐assisted flash lamp annealing exhibit a transmittance of up to 88% at 550 nm and resistivity of 3.1 × 10−3 Ω cm. Transparent touch‐sensing trackpad and capacitive touch sensors are demonstrated based on the printed ITO patterns, which can be utilized in transparent security systems and other transparent Internet‐of‐Things devices.

Additive Nanomanufacturing of Multifunctional Materials and Patterned Structures: A Novel Laser‐Based Dry Printing Process

“…Therefore, printing multifunctional materials (e.g., ferromagnetic, piezoelectric) and hybrid structures is still a major challenge. [17,[26][27][28][29][30][31][32][33][34][35] Direct printing of multifunctional materials and composites such as titanium dioxdie (TiO 2 ), [36][37][38][39][40][41][42] barium titanate (BTO), [43][44][45] indium tin oxide (ITO) [11,46] opens a new pathway toward the direct manufacturing of devices with complex functionality. This has led to the emergence of laser-based additive nanomanufacturing (ANM) as a promising approach that could enable the synthesis and patterning of a variety of materials with micro/nanoscale resolutions.…”

Versatile carbon-loaded shellac ink for disposable printed electronics

“…Various metal-free inks have also been developed based on electroceramics 14 – 16 and intrinsically conductive polymers (ICPs) 17 – 20 . Indium tin oxide (ITO) is the most prominent electroceramic.…”

Invisible and Flexible Printed Sensors Based on ITO Nanoparticle Ink for Security Applications

“…Based on the differential scanning calorimetry (DSC) curve, 250°C was selected previously as an optimal annealing temperature for the low vacuum annealing step of ITO film printed on rigid glass (Gilshtein et al, 2020). However, such thermal annealing requirements limit the flexible substrate choice, which has to be at the same time mechanically stable and transparent.…”

“…Among the known transparent materials, transparent conducting oxides (TCO) are one of the most indispensable materials to fabricate conductive devices and structures, and indium tin oxide (ITO) has become a material of choice for most of those (Jeong et al, 2010;Hwang et al, 2011;Chen et al, 2013;Tue et al, 2016;Gilshtein et al, 2020). Recently, direct printing methods, such as inkjet printing of such material, receive attention due to their advantages (Fang et al, 2013;Datta et al, 2020).…”