Low-dimensional Chalcogenide Based Thermoelectric Composites

Download or read book Low-dimensional Chalcogenide Based Thermoelectric Composites written by Chaochao Dun and published by . This book was released on 2017 with total page 161 pages. Available in PDF, EPUB and Kindle. Book excerpt: By using the hydrothermal reflux method, a series of low-dimensional chalcogenide nanostructures were designed. On one hand, ternary metal (Bi, Cu, Ag, and Pb) chalcogenide nanowires with high thermoelectric figure of merit and power factors were obtained by using Te1-[subscript x]Se[subscript x] alloys as templates. On the other hand, Bi2Se3, Bi2Te3, Sb2Te3 nanoplates and their derivatives were also successfully fabricated. After nanostructures were obtained, we further combine them with polymers such as polyvinylidene fluoride to guarantee their flexibility in thermoelectric devices. Here, the non-conductive polymer can not only guarantee the robustness and flexibility but also create a high trap-state by introducing the energy barrier at the organic/inorganic interface, thus a high level of Seebeck coefficient is maintained while a remarkable improvement on electrical conductivity was achieved. To our best knowledge, we are the first group developing the flexible and freestanding thermoelectric generators based on inorganic chalcogenides nanomaterials. Different morphologies of chalcogenide nanoplates can be well controlled: For example, with different supersaturation status, the growth mode of Sb2Te3 nanoplates can be changed from layer by layer to spiral growth. Surface modification and nanoengineering is utilized, like putting metal ions in the interlayer of n-type Bi2Se3 by taking advantage of its interlayer gaps, or growing self-assembled metal nanoparticles (Ag or Cu) on the lateral edges of n-type Bi2Te3 and p-type Sb2Te3 nanoplates by using their active edges. Unlike any previous studies involved in inorganic systems, the Seebeck coefficient and electrical conductivity can increase in parallel with the introduced self-assembled heterojunction architectures because of the optimized electron and phonon transport behavior. This is one of the exciting achievements we have done in our lab to potentially change the thermoelectrics field.