Contactless In-Situ Electrical Characterization Method of Printed Electronic Devices with Terahertz Spectroscopy

Printed electronic devices are attracting significant interest due to their versatility and low cost; however, quality control during manufacturing is a significant challenge preventing the widespread adoption of this promising technology. We show that terahertz radiation can be used for the in-situ inspection of printed electronic devices, as confirmed through a comparison with conventional electrical conductivity methods. Our in-situ method consists in printing a simple test pattern exhibiting a distinct signature in the THz range that enables the precise characterization of electrical conductivities of the printed ink. We demonstrate that contactless dual-wavelength THz spectroscopy analysis, which requires only a single THz measurement, is more precise and repeatable than the conventional four-point probe conductivity measurement method. Our results open the door to a simple strategy for performing contactless quality control in real time of printed electronic devices at any stage of its production line.