Fig. 3: Working mechanism of thermoelectric generation, measurement platform, and thermoelectric output characteristics of the fabricated DC-ThEG.

a Based on the Seebeck effect, when a heat source is applied to one side of the fabricated DC-ThEG, charge carriers (i.e., electrons in n-type thermoelectric material, Bi₂Te_2.7Se_0.3, and holes in p-type thermoelectric material, Sb₂Te₃) diffuse from the hot side to the cold side, resulting in a current, which can be measured by a digital multimeter connected to the two thermoelectric leg chains. Two switches K₁ and K₂ were used to alternate the working states of the device and testing states of the measurement platform. b Practical temperature changes of the hot side (T₁, red) and cold side (T₂, black) of the DC-ThEG versus the increase in the temperature difference (ΔT). c The open-circuit output voltage (black) and power (red) of the developed DC-ThEG increase as ΔT increases (open-circuit state: K₁-ON, K₂-OFF). d Output power to various external load resistors at different ΔT (load-connected state: K₁-ON, K₂-ON). The maximum value of ~2.9 μW was achieved when ΔT and the load resistance were 50 °C and 1.8 kΩ, respectively