Scalable fabrication of cross-plane thin-film thermoelectric generators on organic substrates

Highlights: • Highly scalable planar process for thermoelectric generators (TEG). • Cross plane configuration. • Length of thermopiles is independent on their thickness. • Competitive thermoelectric perfomance when compared to thick-flim TEGs. Thin-film thermoelectric generators (TFTEGs) can provide energy for ultra-low power devices such as microscale heaters, cooling-units, and autonomous sensors and actuators. Of particular interest are micro- and nano-structured thermoelectric materials deposited on organic substrates, which allow fabrication of ultra-fast Peltier elements, mechanically flexible TFTEGs, and integration of TFTEGs in transparent microfluidic cells. In this study we report on an integration process of bismuth telluride based cross-plane TFTEGs on polyimide as a model material for organic substrates by adapting a well-established planar technology method. The main advantage of this approach is that the length of the thermopiles is independent on the thickness of the thermoelectric materials, which allows for fabrication of TFTEGs with high aspect ratio.