Enhancing the effective mass and covalent bond strength of Cu3SbSe4-based thermoelectric materials by Mn/Sn co-doping

Cu 3 SbSe 4 -based thermoelectric materials , known for their complex crystal structure and splendid Seebeck coefficient , have garnered significant attention. However, a major challenge in this field is further enhancing the thermoelectric performance while effectively controlling the carrier concentration. In this work, a novel doping strategy is proposed to effectively adjust the energy band structure by Mn doping while simultaneously increasing the carrier concentration and the effective mass of the density of states , thereby optimizing the power factor. Additionally, Sn doping is employed to boost the carrier concentration significantly while strengthening the covalent bonds , thereby improving the samples’ stability. As a result, the Cu 3 Sb 0.92 Mn 0.06 Sn 0.02 Se 4 sample achieves a zT value of 0.74 at 673 K. Moreover, the Cu 3 Sb 0.93 Mn 0.06 Sn 0.01 Se 4 sample exhibits an average zT value of 0.39 within the temperature range of 273–675 K. This research sheds light on an approach for designing high-performance Cu 3 SbSe 4 -based thermoelectric materials by manipulating the carrier concentration and enhancing the covalent bond strength through doping.