High Performance µ -Thermoelectric Device based on Bi2Te3/Sb2Te3 p-n Junctions

A flexible and ultralight planar thermoelectric generator based on 15 thermocouples composed by n-type bismuth telluride (Bi2Te3) and p-type antimony telluride (Sb2Te3) legs (each with 400 nm thick) connected in series, on 25 - µm thick Kapton® substrate, was fabricated with impressive power factor values of 2.7 mW K-2 m-1 and 0.8 mW K-2 m-1 (at 298 K) for Bi2Te3 and Sb2Te3 films, respectively. The p-n junction thermoelectric device can generate a maximum open-circuit voltage and output power of 210 mV and 0.7 µW (3.3 mW cm-2), respectively, for a temperature difference of 35 K, which is higher than the one observed for a conventional thermoelectric device with metallic contacts for p-n junctions. The results were combined with numerical simulations showing a good match between the experimental and the numerical results. The current density versus voltage (J-V) characteristics of the fabricated p-n junctions revealed a diode behavior with a turn-on voltage of ≈ 0.3 V and an impressive rectifying ratio (I+...