Screen Printed Thermoelectric Devices

Abstract

Thermoelectric generators (TEG) directly convert heat energy into electrical energy. The impediments as to why this technology has not yet found extensive application are the low conversion efficiency and high costs per watt. On the one hand, the manufacturing process is a cost factor. On the other, the high--priced thermoelectric (TE) materials have an enormous impact on the costs per watt. In this thesis both factors will be examined: the production process and the selection of TE materials. Technical screen printing is a possible way of production, because this method is very versatile with respect to the usable materials, substrates as well as printing inks. The organic conductor PEDOT:PSS offers reasonable thermoelectric properties and can be processed very well in screen printing. It was demonstrated by prototypes of fully printed TEGs that so--called vertical printed TEGs are feasible using standard graphic arts industry processes. In addition, the problems that occur with print production of TEGs are identified. Finally, approaches to solve these problems are discussed.

Fabrication and Characterization of PLD-Grown Bismuth Telluride (Bi<sub>2</sub>Te<sub>3</sub>) and Antimony Telluride (Sb<sub>2</sub>Te<sub>3</sub>) Thermoelectric Devices

“…To characterize the thermoelectric performance, Altenkirch found that a dimensionless figure of merit can provide a better indication of the thermoelectric quality of a material than Seebeck or Peltier effects [1] [2] [3]. This figure of merit, ZT, can be expressed as…”

“…From Equation (3), it can be observed that a material with good thermoelectric properties should have high σ, high S, and low k. For a device built using n-type and p-type materials, the figure of merit, ZT, can be obtained from the following Equation [1]: …”

Multi-Physics Numerical Simulation of Thermoelectric Devices

“…With the advancement in material engineering and device fabrication, these devices have become more efficient and are being used in many applications. These devices are mainly divided into two major groups: The first group is based on Peltier effect [1] [2] [3] [4] and is used in cooling and refrigeration applications [5] [6]. These devices can be used in cooling or heating integrated circuits, biological and medical elements, medical sensors and devices, and other applications; The second group is based on Seebeck effect [2] [3] and is mainly used in energy harvesting [1] [7]- [12].…”

“…They can be from the Chalcogenides [13] [14] [15], the Skutterudites [4], the Half Heusler [16], the Clathrates [17] [18], and the TAGS [19] [20]. The most promising materials are the compounds based on Bismuth Telluride (Bi 2 Te 3 ) and Antimony Telluride (Sb 3 Te 3 ) [21] [22].…”

Advanced Manufacture by Screen Printing

“…Optimising these parameters can both improve print performance and overcome print defects such as mesh marking, pinholes and crowning, as well as irregularities in printed lines. Mesh marking is the appearance of regular features corresponding with the frequency of the mesh in the printed solid film (20,25,26). This causes increases in the print roughness and can cause issues when depositing multiple layers.…”