Pop-up kirigami thermoelectric generator with high stretchability and conformal thermal interfaces

Abstract Thermoelectric generators (TEGs), which convert temperature differences in the environment into electrical energy, have attracted attention as power sources for sensing devices. However, because most heat sources in the environment possess curved surfaces, TEGs must be both bendable and stretchable. We propose a flexible TEG using a pop-up kirigami structure obtained by cutting a defined pattern into the substrate. Our pop-up kirigami TEG has conformable thermal contact and cooling surfaces as well as high bendability and stretchability. As a result, the pop-up kirigami TEG exhibits higher output power compared with conventional flexible TEGs and also shows stable power generation even against curved heat sources. In addition, we attached the pop-up kirigami TEG to human skin and succeeded in capturing changes in human body temperature. Therefore, the proposed pop-up kirigami TEG can be expected to greatly promote the spread of Internet of Things sensors and wearable devices in the future.