As the best-performing materials for thermoelectric cooling,Bi_(2)Te_(3)-based alloys have long attracted attention to optimizing the room-temperature performance of Bi_(2)Te_(3) for both power generation and refriger...As the best-performing materials for thermoelectric cooling,Bi_(2)Te_(3)-based alloys have long attracted attention to optimizing the room-temperature performance of Bi_(2)Te_(3) for both power generation and refrigeration applications.This focus leads to less emphasis and fewer reports on the cooling capability below room temperature.Given that the optimal carrier concentration(nopt)for maximizing the cooling power is highly temperature dependent,roughly following the relationship nopt/T3/2,lowering the carrier concentration is essential to improve the cooling capability at cryogenic temperatures.Taking p-type Bi_(0.5)Sb_(1.5)Te_(3) as an example,careful control of doping in this work enables a reduction in carrier concentration to 1.7×10^(19) cm^(-3) from its optimum at 300 K of 3.4×10^(19) cm^(-3).This work successfully shifts the temperature at which the thermoelectric figure of merit(zT)peaks down to 315 K,with an average zT as high as 0.8 from 180 to 300 K.Further pairing with commercial n-type Bi_(2)Te_(3)-alloys,the cooling device realizes a temperature drop as large as 68 K from 300 K and 24 K from 180 K,demonstrating the extended cooling capability of thermoelectric coolers at cryogenic temperatures.展开更多
基金National Natural Science Foundation of China,Grant/Award Numbers:T2125008,92263108,92163203,52102292Shanghai Rising-Star Program,Grant/Award Number:23QA1409300Innovation Program of Shanghai Municipal Education Commission,Grant/Award Number:202101-07-00-07-E00096。
文摘As the best-performing materials for thermoelectric cooling,Bi_(2)Te_(3)-based alloys have long attracted attention to optimizing the room-temperature performance of Bi_(2)Te_(3) for both power generation and refrigeration applications.This focus leads to less emphasis and fewer reports on the cooling capability below room temperature.Given that the optimal carrier concentration(nopt)for maximizing the cooling power is highly temperature dependent,roughly following the relationship nopt/T3/2,lowering the carrier concentration is essential to improve the cooling capability at cryogenic temperatures.Taking p-type Bi_(0.5)Sb_(1.5)Te_(3) as an example,careful control of doping in this work enables a reduction in carrier concentration to 1.7×10^(19) cm^(-3) from its optimum at 300 K of 3.4×10^(19) cm^(-3).This work successfully shifts the temperature at which the thermoelectric figure of merit(zT)peaks down to 315 K,with an average zT as high as 0.8 from 180 to 300 K.Further pairing with commercial n-type Bi_(2)Te_(3)-alloys,the cooling device realizes a temperature drop as large as 68 K from 300 K and 24 K from 180 K,demonstrating the extended cooling capability of thermoelectric coolers at cryogenic temperatures.
