Measurement System to Determine the Seebeck Coefficient and Electrical Conductivity of Thin Films

Thermoelectric (TE) materials are promising for energy-generating devices, and their design depends on a fast, precise determination of their Seebeck coefficient and electrical conductivity. Herein, a low-cost setup was developed to determine the Seebeck coefficient and electrical conductivity of thin films, allowing the calculation of the power factor (PF) <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$(\text {PF}=S^{2}\sigma)$ </tex-math></inline-formula>. The system was validated by measuring the Seebeck coefficient and electrical conductivity of poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS), a widely used material in organic electronics and TE generators. The results demonstrate the high resolution of our system, with obtained values of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.1~\mu \text {V/K}$ </tex-math></inline-formula> for Seebeck coefficient, <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.1~\text {S/cm}$ </tex-math></inline-formula> for electrical conductivity, and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.1~\mu \text {W/K}^{2}$ </tex-math></inline-formula> for PF. A detailed description of the fabrication of the measurement setup is provided, with the aim of making thermoelectricity accessible to any research laboratory, even in places with limited budgets.