Predictable thermoelectric performance of directly synthesized Bi0.5Sb1.5Te3 using laser powder bed fusion additive manufacturing

Laser powder bed fusion (LPBF) additive manufacturing, as a novel technique provides broad benefits in thermoelectric materials synthesis, such as enhanced printing speed, reduced waste materials, and customized dimension design. The high energy density of laser could potentially balance the synthesis rate and thermoelectric figure-of-merit zT, but the correlations between laser energy and material performance are still vague. Herein, Bi0.5Sb1.5Te3 bulks are directly synthesized by LPBF with a recorded synthesis rate of 254 g h-1. The maximum zT, without any post-processing, reaches 1.1 at 75 degrees C. Induced nanoscale pores by high laser energy printing, obtain a comparable diameter to phonon mean free path, leading to reduced lattice thermal conductivity and enhanced TE performance. We found that input laser energy critically affected thermoelectric performance and concluded the correlation between volumetric energy density EV and power factor PF, PF = 9.05EV2 - 30.01EV + 48.84. It potentially predicts thermoelectric performance with inputted laser energy density.