High thermoelectric power factor of n-type Bi₂(Se,S)₃ via synergetic influence on the charge carrier concentration and energy filtering effect

Excellent thermoelectric performance is sought to address essential energy concerns, including the impact of energy consumption on the environment. In this work, we have synthesized the Bi₂Se₃ thin film using a simple thermal evaporation route and post‑sulfurized it for different durations at (773 K). The crystal structure change from rhombohedral to orthorhombic with different post‑sulfurization times has been confirmed via x-ray diffraction. The atomic vibrational modes of Bi₂(Se,S)₃ thin films have been examined by Raman spectroscopy. The surface morphology of Bi₂(Se,S)₃ thin films have been observed using a scanning electron microscope. The Seebeck coefficient values enhanced from 155.1 to 203.5 μV/K with post‑sulfurization time due to increased charge carrier concentration and energy filtering effect. The electrical conductivity improved from 90.2 to 118.7 S/m of the as-deposited sample to the highest post‑sulfurized sample due to improving charge carrier concentration and changing the crystal structure from rhombohedral to orthorhombic structure. We have achieved the maximum power factor of Bi₂(Se,S)₃ thin film of the 4.86 μWcm⁻¹ K⁻² at room temperature. Obtaining the highest power factor has a straightforward approach to fabricating commercial thermoelectric material.