Tuned Fermi Level and Improved Thermoelectric Performance in Bi2Te3Nanocomposites Reinforced with g-C3N4Nanosheets

Bi2Te3 has been recognized as an efficient and scalable thermoelectric material suitable for sustainable power generation and environment friendly cooling. Nano structuring and adding nano inclusions in the bulk thermoelectric material offers cost effective and scalable strategy to attain reduced thermal conductivity and improved figure of merit. Here, we report inclusion of g-C3N4 nanosheets in Bi2Te3 to tune the thermoelectric properties of the matrix. The g-C3N4/Bi2Te3 nanocomposites were synthesized through solid state reaction route, ball milling and hot pressing techniques. The fermi level shift is evaluated for the prepared samples by using Fritzsche model. The shift in fermi level away from the conduction band edge explains observed enhancement in seebeck coefficient. The incorporated nanosheets effectively scatters phonons leading to diminished thermal conductivity and improved ZT. ZT peaks to 0.34 at 448 K for the sample BT1CN with 1 wt.% of g-C3N4.