Enhanced thermoelectric performance of n-type polycrystalline AgBiSe2 via CeCl3 doping

At present, Ag-based thermoelectric materials have received extensive attention and have demonstrated excellent performance in related device application. Among them, AgBiSe 2 is a lead-free thermoelectric material that exhibits significant n -type doping characteristics. It has been previously reported that R Cl 3 -doping ( R denotes the rare earth elements) has achieved excellent results in some n -type thermoelectric materials. However, there is still a lack of systematic research on the effect of R Cl 3 doping on AgBiSe 2 based materials. In this work, n -type AgBiSe 1.98 polycrystalline materials doped with CeCl 3 (0.5–2 mol%) are successfully synthesized by the melting method in combination with spark plasma sintering (SPS) technique. Compared with AgBiSe 2 , the CeCl 3 -doped AgBiSe 1.98 samples have achieved a significant increase in thermoelectric figure of merit ( ZT ) value, which should be attributed to the higher power factor ( PF = S 2 σ ) and inherently low thermal conductivity. Specifically, a large ZT max of ∼ 0.65 is achieved at 733 K in the 2 mol% CeCl 3 -doped AgBiSe 1.98 sample, which shows an increase of 41 %. This study demonstrates that CeCl 3 -doping, as a novel strategy that can improve simultaneously n H and m *, reveals excellent optimization effects in the thermoelectric performance regulation of AgBiSe 2 -based materials.