Formulation and optimization of copper selenide/PANI hybrid screen printing ink for enhancing the power factor of flexible thermoelectric generator: A synergetic approach

The stunning thermoelectric behavior of inorganic/organic hybrids and the lack of information on screen-printed flexible thermoelectric generators based on Cu₃Se₂ and Polyaniline for low-temperature applications have motivated this work. The synergic influence of various acid dopants, concentration, and annealing temperature of polyaniline on the power density of Cu₃Se₂/PANI ink-based flexible thermoelectric generator is explored. The presence of 1.5 wt% of H₂SO₄-PANI, annealed at 60 °C, decreased the bandgap and electrical resistance of Cu₃Se₂ by 11.96 % and 29.4 %, respectively. As a result, an increase of 46.06 % in the Seebeck coefficient and 242 % in the power output is achieved, which is many folds higher than the few reported works using novel materials. In addition, the Cu₃Se₂/H₂SO₄-PANI ink-based flexible thermoelectric generator with eight legs exhibited a maximum power output, power density, and power factor of 25.69 nW, 23.79 mW/m^2, and 0.77 nW/m²K² at ΔT = 100 °C, respectively under external load.