For zone-melted (ZM) bismuth telluride-based alloys,which are widely commercially available for solid-state cooling and low-temperature power generation around room temperature,introducing point defects is the chief approach to improve their thermoelectric performance.Herein,we report the multiple effects of Se doping on thermoelectric performance of p-type Bi0.5Sb1.5Te3-xSex + 3 wt％ Te ZM ingots,which increases carrier concentration,reduces lattice thermal conductivity and deteriorates the carrier mobility.As a result,the peak figure of merit (ZT) is shifted to a higher temperature and a high ZT ～ 1.2 at 350 K is obtained,due to the reduced thermal conductivity and suppressed intrinsic conduction.Further,decreasing Sb content is followed to optimize the room temperature performance and a ZT ～ 1.1 at 300 K is obtained.These results are significant for designing and optimizing the thermoelectric performance of commercial Bi0.5Sb1.5Te3+ 3 wt％ Te ZM alloys.