UV-curable silver electrode for screen-printed thermoelectric generator

Abstract

Fabricating thermoelectric generators (TEGs) using the screen-printing process has advantages, including mass production, device scalability, and system applicability. However, the thick film formed through the process typically has low film density, and reduced performance, because of the presence of pores in the film created by the vaporization of the resin during high-temperature annealing. During the soldering process used for thermoelectric module fabrication, the printed solder infiltrates into the screen-printed electrodes through the micropores in the electrodes, causing cracks of the electrode film and an increase in resistivity. In this paper, an ultraviolet radiation (UV)-curable process for screen-printed electrodes is reported. The paste for the electrodes is synthesized by mixing Ag flakes that can be cured at low temperature with a UV resin. Scanning electron microscope images show that the UV-curing process significantly reduces pores and thereby results in a smooth-surfaced electrode layer. The film density after crystallization is also enhanced. TEGs composed of 72 couples with UV-curable Ag electrodes generate a high power density of approximate to 6.69 mW cm(-2) at a temperature difference of 25 degrees C; the device resistance is approximate to 0.75 , and the figure of merit of the device is recorded to be 0.57, which is the highest among the printed TEGs.