EU Project 3Plast

Within the 3PLAST project, funded by the European Union, ink pastes and processing technologies were developed to reduce the complexity of multi-component sensor devices. By using only five non-toxic inks a low-cost and sustainable manufacturing technique for flexible large-area printed organic electronics was created. The project is organized by Fraunhofer ISC with Joanneum Research as the scientific coordinator.

The 3PLAST all-printed active-matrix sensor array utilizes a ferroelectric polymer from the class of PVDF (poly(vinylidene fluoride)) that can be applied by screen printing in a highly crystalline form on a PET substrate. After poling in an electric field, this ferroelectric layer is very sensitive to small changes in temperature and/or pressure. The sensitivity is very stable,both in time and with respect to stress tests, and the printed transistor is perfectly adapted to the sensor, especially in  terms of impedance and range of operation voltage, providing an optimized amplification of the sensor signal.

Finally, the sensor arrays were combined with printed electrochromic displays developed at the 3PLAST partner Acreo, to form an all-printed position-sensitive input device, which supports touchless control. Both, movement of a finger in front of a sensor spot and illumination of the sensor spot with a laser pointer, activate the connected display segment. The printed sensor responds fast enough to monitor hand and finger movements. Even simple gesture control functions were successfully demonstrated, paving the way to printed and polymer-based touchless interface devices. Furthermore, the piezoelectricity of the printed sensor also enables touchbased control as was shown by the Johannes-Kepler-University, another 3PLAST partner ( Movie : Click HERE )

The all-printed sensor technology developed in the 3PLASTsensor project shows that complex devices comprising various classes of electronic components, such as pressure- and temperature-sensitive sensors, organic transistors as well as electrochromic displays, can easily be integrated monolithically on a flexible substrate by utilizing only five inks: PEDOT:PSS, carbon, P(VDF-TrFE), electrolyte and SU-8. A fabrication method combining simple printing processes with a small number of materials is more practical, produces higher yields, and costs less than common polymer sensor network production methods. The development carried out in the 3PLAST project demonstrate, that low-cost fabrication routes enable a new generation of large-area flexible control interfaces. Such devices may prove useful as conformable keypads for both, touch-based and non-touch based operation.