Enhanced thermoelectric properties of bismuth telluride via Ultra-Low thermal conductivity BOSC compound addition

• Ultra-low thermal conductivity BOSC was added to bismuth telluride for the first time. • The minimum value of κ tot is 0.54 W m –1 K –1 at 150 °C for 1 wt% BOSC. • The maximum ZT value observed for the 1 wt% BOSC sample was 0.86 at 150 °C. • ZT value of 1 wt% BOSC was about four times that of the bare bismuth telluride sample. This study aimed to enhance the thermoelectric properties of bismuth telluride by adding Bi 4 O 4 SeCl 2 (BOSC). Commercial N-type bismuth telluride was mixed with BOSC powder in varying concentrations. As the BOSC content increased, the carrier concentration also rose due to chlorine atoms acting as donor impurities. Despite this increase, the power factor values of the samples with BOSC additives did not significantly differ from those of the bare bismuth telluride sample. However, the total thermal conductivity decreased significantly with the addition of BOSC, reaching a minimum value of 0.54 W·m –1 ·K –1 at 150 °C for the sample with 1 wt% BOSC. Notably, the ZT value for the sample with 1 wt% BOSC was about 0.86, which is four times higher than that of the bare bismuth telluride sample. Our findings demonstrate superior thermoelectric performance, indicating a more efficient modification of thermoelectric properties through the addition of BOSC to the bismuth telluride matrix .