3D Interconnected Nanowire Scaffoldings that Increase the Thermoelectric Efficiency in Comparison to Similar Diameter 1D Nanowires

We will present how 3D interconnected nanowire scaffoldings can increase the thermoelectric efficiency in comparison to similar diameter 1D nanowires and films grown under similar electrodeposition conditions. Bi₂Te₃ 3D nanonetworks offer a reduction in thermal conductivity (κT) while preserving the high electrical conductivity of the films. The reduction in κT is modeled using the hydrodynamic heat transport equation, and it can be understood as a heat viscosity effect due to the 3D nanostructuration or to additional scattering centers. The Seebeck coefficient is twice that of nanowires and films, and up to 50% higher than in a single crystal. This increase is interpreted as a nonequilibrium effect that the geometry of the structure induces on the distribution function of the phonons, producing an enhanced phonon drag. These thermoelectric metamaterials have higher performance and are fabricated with large areas by a cost-effective method, which makes them suitable for up-scale production. Other studies have also explored the transport properties of Bi₂Te₃ nanowires, including low temperature magnetoresistance measurements and local magnetic suppression of topological surface states. The crystalline structure and composition of the 3D Bi₂Te₃ nanowire network can be finely tuned by controlling the applied voltage and the relaxation. These findings have important implications for the development of macroscopic nanostructured thermoelectric materials based on scalable fabrication processes that could be directly integrated into devices.The study of the localization and directionality of electron transport in Bi₂Te₃ ordered 3D nano-networks is a fascinating area of research. In this study, the resistance of an ordered 3D-Bi₂Te₃ nanowire nano-networks were analyzed at low temperatures, and the increase in resistance below 50 K was found to be compatible with the Anderson model for localization.<br/>The angle-dependent magnetoresistance measurements showed a unique weak anti-localization characteristic with a double feature, which could be associated with transport along two perpendicular directions dictated by the spatial arrangement of the nanowires. The coherence length obtained from the HLN model was about 700 nm across transversal nanowires, corresponding to approximately 10 nanowire junctions. The observed localization effects could be the reason for the enhancement of the Seebeck coefficient observed in the 3D-Bi2Te3 nanowire nano-network compared to individual nanowires. This research has important implications for the development of macroscopic nanostructured thermoelectric materials based on scalable fabrication processes that could be directly integrated into devices.