Enhanced thermoelectric properties of Ag2Se by manipulation in carrier concentration via acetylene carbon black nanocomposites

• Acetylene carbon black (ACB) addition in bulk Ag 2 Se. • Enhance thermoelectric performance of the composites. • Thermal conductivity reduces from 2.0 to 0.9 W/mK at 383 K. • 5.0 wt% of ACB achieves a highest zT of 0.8 at 383 K. Pristine Ag 2 Se has inherent limitations in its Seebeck coefficient and electronic thermal conductivity, necessitating improvements through carrier concentration manipulation. While its porous structure has been utilized to reduce carrier concentrations, achieving optimal values remains challenging. This study explores enhancing Ag 2 Se with acetylene carbon black (ACB) nanocomposites to further reduce carrier concentrations and improve thermoelectric (TE) properties. ACB, a cost-effective alternative to other carbon materials, has demonstrated potential in enhancing TE performance in various composites. Ag 2 Se and ACB composites were synthesized by dispersing different ACB weights in a solution, followed by sintering. Characterization using x-ray diffraction (XRD), Transmission and scanning electron microscopy (TEM and SEM), and other techniques confirmed the phase, structure, and morphology of the composites. The addition of ACB resulted in decreased electrical conductivity and increased Seebeck coefficient in Ag 2 Se, particularly at ACB concentrations up to 5.0 wt%, balancing the power factor ( PF ). The total thermal conductivity decreased due to mainly reduced electronic thermal conductivity. The 5.0 wt% ACB sample achieved a zT of approximately 0.8 at 383 K, comparable to the performance of composites using more expensive low-dimensional carbon materials.