Research

The research activities of the FME group are focused on printing and coating technology (mainly screen printing, inkjet printing and ultrasonic spray coating) for their application in Organic and Perovskite Electronics, Printed Sensors for health monitoring, Structural Electronics, and (liquid metal-based) Stretchable Electronics.

Research lines

Our group is mainly focusing on sustainable deposition of innovative materials and the layer formation linked to this deposition. As an engineering tool, printing and coating can be applied to achieve large area devices (as compared to for example spin coating) or for energy-efficient deposition in contrast to vacuum deposition. Moreover, the integration in the Institute for Materials Research (imo-imomec) provides access to state-of-the-art device fabrication and (optoelectronic) characterization tools. All projects are conducted in close collaboration with colleagues from chemistry for innovative materials, over physics for device characterization towards engineering for health and energy applications and upscaling.

Health sensors

The main aim within this research line is the development of printed sensors for wound monitoring. When a wound is healing, its parameters such as temperature, pH and moisture level and composition are constantly changing. Measuring these with printed sensors integrated in wound bandages can lead to a better understanding of the wound healing process and therefore also to a faster healing. Moreover, from a sustainability perspective, printed devices can be applied for one-time, recyclable sensing combined with re-usable (not necessarily printed) read-out electronics. Spill overs of this research are the monitoring of other body parameters in a hybrid approach (combining sensors in textiles and sensors on e-tattoo’s (i.e. skin adhesives)) or monitoring of the status of fruit growth and fruit trees.

Stretchable electronics

In this research line, the use of liquid metal as a conductive material that is liquid at room temperature, is applied. Galinstan, an alloy of Gallium, Indium and Tin is such a liquid metal that can be deposited on a stretchable substrate (such as silicones or polymeric substrates) via stencil-based spray coating or dispensing. This way liquid metal circuits and interconnects can be build within an elastomeric encapsulation. Applying other electronic components (such as LEDs, batteries or even small ICs) in the soft and stretchable device leads to a step from rigid, surpassing flexible electronics, towards stretchable PCBs. Optimizing the deposition process, studying the degradation upon multiple stretching and more and more complex electronic devices are among the targets.

Structural electronics

The combination of screen printing on one-time deformable substrates is combined in this research line with thermal forming to achieve 3D circuits. For this, flexibility of the printed circuits is a necessity. Applying conductive adhesives to add SMD components (LEDs, …) on the circuits leads to hybrid electronics (combination of printing and SMD components) in, what is called structural electronic devices, i.e. hybrid electronics in a 3D shape. Investigation towards flexible materials for printing, their interaction with the SMD components and the stability during forming are investigated and further steps involve the integration of the printed circuits on foil into a molding process.

Light emission

Light emission can be achieved by applying layers with different functionalities on top of each other. Anorganic Light Emitting Devices (also called AC-powered Electroluminescent devices) are constructed in a capacitor structure to emit light when approx. 80 V (in AC) is applied. Printed Light Emitting Diodes (LEDs) are achieved when applying organic or perovskite materials for the emissive layer and a DC-voltage of only 4-7 V is applied. Optimizing the luminescent properties of these devices by optimizing the materials used (for example introducing polymer-nanoparticle blends), studying deposition technologies to achieve ultrathin large area coatings (spray-on-screen) and studying the droplet behaviour of the ultrasonically sprayed formulation when flying from nozzle to substrate is studied. A recent focus on Near Infrared emission (using carbon nanotubes) links this research with applications in healthcare for example for photobiomodulation and thus wound healing.