Optimizing Bi2Te3 Thin Film Thickness for Enhanced Thermal Conductivity and Thermoelectric Performance of a Bi2Te3 Thermoelectric Generator
摘要
Thermoelectric generators (TEGs) hold significant promise as a method for converting heat into electricity by leveraging the Seebeck effect, alongside various other renewable energy harvesting techniques. Thermoelectric (TE) measurements suggest that optimizing the thickness and thickness ratio enhances the TE performance of Bi2Te3 thin films in comparison to their bulk counterparts. To investigate the impact of varied thickness, Bi2Te3 nanoparticles were first synthesized through a straightforward one-pot hydrothermal process. Subsequently, thin films with thickness ranging from 50 nm to 250 nm were deposited using thermal evaporation in order to achieve optimized TE performance. X-ray diffraction, field-emission scanning electron microscopy (FESEM), and Raman spectroscopy analyses validated the fabrication of Bi2Te3 thin films. In addition, 3-omega measurements were conducted utilizing flexible heaters to assess the impact of thickness on thermal conductivity, revealing a decrease from 1.80 W m−1 K−1 to 0.38 W m−1 K−1. In the planar configuration, the highest observed value for the Seebeck coefficient in the 200-nm-thick film reached 562 μV K−1, with a maximum ZT value of 1.01. The TE characteristics of the optimized p-type Bi2Te3 -based TEGs with a single-TE-leg configuration comprising 10 TE legs with gold (Au) as the electrical contact, exhibit an enhanced Seebeck coefficient of 473 μV/K at room temperature (RT), along with TE voltage generation of 0.8 V.