Thermoelectric materials can directly achieve the conversion between heat and electricity,providing a clean and reliable way to alleviate energy crisis.However,the wide use of thermoelectric materials is subjected to ...Thermoelectric materials can directly achieve the conversion between heat and electricity,providing a clean and reliable way to alleviate energy crisis.However,the wide use of thermoelectric materials is subjected to their low energy conversion efficiency.Grain boundary engineering is considered as an effective strategy to improve thermoelectric performance,particularly for the most polycrystalline thermoelectric materials in bulk state.Recently,the precise controlling over the microstructure and composition of grain boundary at atomic scale has been achieved by atomic layer deposition(ALD)technology,which has been confirmed in various thermoelectric materials,such as Bi2Te2.7Se0.3,Bi0.4Sb1.6Te3,and ZrNiSn.Importantly,it is demonstrated that the decoupling between three key thermoelectric parameters,i.e.Seebeck coefficient,electrical conductivity and thermal conductivity,can be realized by ALD-based grain boundary engineering.Moreover,these key parameters can be optimized simultaneously toward the desired direction,which is extremely important for improving the thermoelectric performance.In this review,the relevant progress on the grain boundary engineering by ALD-based strategy is reviewed and some prospects are proposed.展开更多
基金supported by the National Natural Science Foundation of China(No.21905007)Guangdong Key Lab Project(No.2017B0303010130)Shenzhen Science and Technology Research Grant(No.JCYJ20150629144612861,JCYJ20150827155136104)。
文摘Thermoelectric materials can directly achieve the conversion between heat and electricity,providing a clean and reliable way to alleviate energy crisis.However,the wide use of thermoelectric materials is subjected to their low energy conversion efficiency.Grain boundary engineering is considered as an effective strategy to improve thermoelectric performance,particularly for the most polycrystalline thermoelectric materials in bulk state.Recently,the precise controlling over the microstructure and composition of grain boundary at atomic scale has been achieved by atomic layer deposition(ALD)technology,which has been confirmed in various thermoelectric materials,such as Bi2Te2.7Se0.3,Bi0.4Sb1.6Te3,and ZrNiSn.Importantly,it is demonstrated that the decoupling between three key thermoelectric parameters,i.e.Seebeck coefficient,electrical conductivity and thermal conductivity,can be realized by ALD-based grain boundary engineering.Moreover,these key parameters can be optimized simultaneously toward the desired direction,which is extremely important for improving the thermoelectric performance.In this review,the relevant progress on the grain boundary engineering by ALD-based strategy is reviewed and some prospects are proposed.
