A simple approach to realize homogeneous ceramic thick films by inkjet printing

Inkjet printing is the most frequently used digital technique for graphic printing. Recently, there has also been a large interest in using inkjet printing for the manufacturing of functional components such as electronic circuits, light emitting diodes (LEOs) or sensor systems. This is due to the fact that inkjet printing is a contactless method. It allows a cheap and flexible production of two- and three-dimensional structures on a wide variety of substrates directly from a digital model. However, the so-called coffee stain effect is a general problem when ceramic suspensions are used as inks. It is caused by a flow of liquid from the center to the edge of a drying drop and leads to a non-uniform deposition of particles. The approaches to prevent the coffee stain effect that are reported in the literature make use of various physical phenomena such as the Marangoni flow to obtain homogeneous thick films. We present a simple ceramic approach, which follows a consideration: Coffee stain effect can be suppressed by a sufficiently fast increase of viscosity after the deposition. This simple approach to fabricate homogeneous ceramic thick films will be presented using the example of (Ba,Sr)Ti03 inks.