Polymerizable Ceramic Ink System for Thin Inkjet-Printed Dielectric Layers

Abstract

An innovative ceramic ink system for thin inkjet-printed dielectric layers is presented, with which it is possible to avoid undesired drying effects. This system contains surface-modified Ba0.6Sr0.4TiO3 (BST) particles, a cross-linking agent, and a thermal radical initiator. The polymerization starts immediately after the ink drop contacts the heated substrate and therefore leads to very homogeneous topographies. Since an organic/inorganic composite ink is used, no sintering is needed after printing and thus printing on flexible substrates is possible. A comparison of the printing and drying behavior between modified and nonmodified BST with the described ink system is performed. The successful surface modification is confirmed via X-ray photoelectron spectroscopy (XPS). Topographies of different printed structures are compared by white light interferometry, the occurring polymerization is confirmed by measurements with an oscillatory rheometer, layer thicknesses are determined by scanning electron microscopy (SEM) images, and the capacitance of a printed capacitor is measured via impedance spectroscopy. It is successfully shown that the developed ink system enables the production of thin ceramic layers (<1 μm) with very homogeneous topographies since undesired drying effects can be avoided. The printed dielectric layers on flexible substrates have a high ceramic content and a high permittivity of 40.

High‐Resolution 3D Printing for Electronics

“…Reinheimer et al produced a thin dielectric layer through inkjet printing of polymerizable ceramic ink. [91] The hybrid ink is composed of surface-modified BST particles, a cross-linking agent, and a thermal radical initiator. Polymerization of ink occurs immediately on the heated substrate, and a homogeneous topography is formed.…”

“…Copyright 2018, Springer Nature. l) Reproduced with permission [91]. Copyright 2020, American Chemical Society.…”

Recent Advances in Multi-Material 3D Printing of Functional Ceramic Devices

“…However, it is still a challenge to print very thin (<1 µm) and uniform dielectric layers that do not achieve the undesirable phenomenon known as the coffee stain effect during the drying stage [ 204 ]. To overcome this intrinsic problem, Reinheimer et al [ 188 ] developed an innovative polymer/ceramic ink system comprising surface-modified (3-(trimethoxysilyl)propyl methacrylate) Ba 0.6 Sr 0.4 TiO 3 particles, a cross-linking agent (poly(ethylene glycol) diacrylate), and a thermal radical initiator (dimethyl 2,2′-azobis(2-methylpropionate)), which allows immediate solidification of the ink. The fully inkjet-printed capacitor with a 700 nm dielectric layer showed a capacitance density of ≈500 pF/mm 2 .…”

Microstructures in All-Inkjet-Printed Textile Capacitors with Bilayer Interfaces of Polymer Dielectrics and Metal–Organic Decomposition Silver Electrodes

“…The role of chemistry in applied materials for wearable electronics is often boundless, with an infusion of organic and inorganic materials in the same devices creating unique interfacial structures. For example, the electrodes in e-textiles can be fabricated by conductive yarns (i.e., stainless steel fibers and metal-coated fibers), metal nanoparticles (i.e., silver nanowires and copper nanoparticles), conductive polymers (i.e., PEDOT:PSS and polypyrrole), and carbon-based nanomaterials (i.e., carbon nanotube , and graphene), dielectrics can be fabricated by polymers [i.e., poly­(vinylidene fluoride) and poly­(4-vinyl phenol) (PVP) and ceramics (i.e., barium titanate , and hafnium oxide), and semiconductors can be processed from traditional inorganic materials (i.e., zinc oxide and titanium dioxide) and organic materials (i.e., pentacene and P3HT). However, with all the available materials, flexible electronics on textile platforms have significant limitations of processability and cost-benefit efficiency. ,, Therefore, e-textiles have often employed diverse methods of combining the aforementioned materials through processing strategies such as chemical vapor deposition, dip coating, screen printing, inkjet printing, and 3D printing .…”