3D Bioplotter Research Papers

Complex shapes are created from Yb14MnSb11, a high-temperature thermoelectric Zintl phase, via a two-step process: i) layer-by-layer 3D-extrusion of ink containing partially-reacted powders which are ball-milled from a blend of Yb, MnSb, and Sb powders; ii) heat treatment to synthesize the ternary compound Yb14MnSb11 and densify the extruded powders. A high phase purity for Yb14MnSb11 (83–94%) is achieved in both cast and 3D-extruded ink specimens via a solid-state reaction between Yb, MnSb, and Yb4Sb3 during reactive sintering. Pressure-free sintering at temperatures of 1200–1400 °C densifies the powders to 82% relative density but can also induce the decomposition of the Yb14MnSb11 phase…

Insulating polymer composites with conductive filler particles are attractive for sensor applications due to their large piezoresistive response. Composite samples composed of a polymer matrix filled with particles of doped semiconductor that gives a piezoresistive response that is 105 times larger than that of bulk semiconductor sensors are prepared here. The piezoresistance of such composite materials is typically described by using a tunneling mechanism. However, it is found that a percolation description not only fits prior data better but provides a much simpler physical mechanism for the more flexible and soft polymer composite prepared and tested in this study. A…

Whereas the rigid nature of standard thermoelectrics limits their use, flexible thermoelectric platforms can find much broader applications, for example, in low-power, wearable energy harvesting for internet-of-things applications. Here we realize continuous, flexible thermoelectric threads via a rapid extrusion of 3D-printable composite inks (Bi2Te3 n- or p-type micrograins within a non-conducting polymer as a binder) followed by compression through a roller-pair, and we demonstrate their applications in flexible, low-power energy harvesting. The thermoelectric power factors of these threads are enhanced up to 7 orders-of-magnitude after lateral compression, principally due to improved conductivity resulting from reduced void volume fraction and partial…