In thermoelectrics,doping is essential to augment the figure of merit.Traditional strategy,predomina ntly heavy doping,aims to optimize carrier concentration and restrain lattice thermal conductivity.However,this tact...In thermoelectrics,doping is essential to augment the figure of merit.Traditional strategy,predomina ntly heavy doping,aims to optimize carrier concentration and restrain lattice thermal conductivity.However,this tactic can severely hamper carrier transport due to pronounced point defect scattering,particularly in materials with inherently low carrier mean-free-path.Conversely,dilute doping,although minimally affecting carrier mobility,frequently fails to optimize other vital thermoelectric parameters.Herein,we present a more nuanced dilute doping strategy in GeTe,leveraging the multifaceted roles of small-size metal atoms.A mere 4%CuPbSbTe_(3)introduction into GeTe swiftly suppresses rhombohedral distortion and optimizes carrier concentration through the aid of Cu interstitials.Additionally,the formation of multiscale microstructures,including zero-dimensional Cu interstitials,one-dimensional dislocations,two-dimensional planar defects,and three-dimensional nanoscale amorphous GeO_(2)and Cu_(2)GeTe_(3)precipitates,along with the ensuing lattice softening,contributes to an ultralow lattice thermal conductivity.Intriguingly,dilute CuPbSbTe_(3)doping incurs only a marginal decrease in carrier mobility.Subsequent trace Cd doping,employed to alleviate the bipolar effect and align the valence bands,yields an impressive figure-of-merit of 2.03 at 623 K in(Ge_(0.97)Cd_(0.03)Te)_(0.96)(CuPbSbTe_(3))_(0.04).This leads to a high energyconversion efficiency of 7.9%and a significant power density of 3.44 W cm^(-2)at a temperature difference of 500 K.These results underscore the invaluable insights gained into the constructive role of nuanced dilute doping in the concurrent tuning of carrier and phonon transport in GeTe and other thermoelectric materials.展开更多
基金supported by the National Key R&D Program of China(2021YFB1507403)the National Natural Science Foundation of China(52071218,and 11874394)+1 种基金the Shenzhen University 2035 Program for Excellent Research(00000218)The University Synergy Innovation Program of Anhui Province(GXXT-2020-003)。
文摘In thermoelectrics,doping is essential to augment the figure of merit.Traditional strategy,predomina ntly heavy doping,aims to optimize carrier concentration and restrain lattice thermal conductivity.However,this tactic can severely hamper carrier transport due to pronounced point defect scattering,particularly in materials with inherently low carrier mean-free-path.Conversely,dilute doping,although minimally affecting carrier mobility,frequently fails to optimize other vital thermoelectric parameters.Herein,we present a more nuanced dilute doping strategy in GeTe,leveraging the multifaceted roles of small-size metal atoms.A mere 4%CuPbSbTe_(3)introduction into GeTe swiftly suppresses rhombohedral distortion and optimizes carrier concentration through the aid of Cu interstitials.Additionally,the formation of multiscale microstructures,including zero-dimensional Cu interstitials,one-dimensional dislocations,two-dimensional planar defects,and three-dimensional nanoscale amorphous GeO_(2)and Cu_(2)GeTe_(3)precipitates,along with the ensuing lattice softening,contributes to an ultralow lattice thermal conductivity.Intriguingly,dilute CuPbSbTe_(3)doping incurs only a marginal decrease in carrier mobility.Subsequent trace Cd doping,employed to alleviate the bipolar effect and align the valence bands,yields an impressive figure-of-merit of 2.03 at 623 K in(Ge_(0.97)Cd_(0.03)Te)_(0.96)(CuPbSbTe_(3))_(0.04).This leads to a high energyconversion efficiency of 7.9%and a significant power density of 3.44 W cm^(-2)at a temperature difference of 500 K.These results underscore the invaluable insights gained into the constructive role of nuanced dilute doping in the concurrent tuning of carrier and phonon transport in GeTe and other thermoelectric materials.
基金supported by the National Natural Science Foundation of China(52071218)Shenzhen Science and Technology Innovation Commission(20200731215211001 and 20200814110413001)Guangdong Basic and Applied Basic Research Foundation(2022A1515012492)。
