The effects of copper-vacancy on the electrical, optical and thermoelectric properties of CuInTe2 have been investigated by the first-principles calculations and semi-classical Boltzmann theory. The estimated results ...The effects of copper-vacancy on the electrical, optical and thermoelectric properties of CuInTe2 have been investigated by the first-principles calculations and semi-classical Boltzmann theory. The estimated results of copper vacancy formation energies for Cu1-xn Te2(x = 0,1/16, 1/8 and 1/4) showed it is more difficult to prepare the sample with higher copper vacancy concentration. From the calculated energy band structures with MBJ-GGA, it can be seen that they are p-type semiconductors and the energy gap values increase with the vacancy concentration increasing. The wavelength is smaller than 460 nm, and the high copper vacancy concentration(x =1/4) is helpful to the values of absorption coefficient, while above 460 nm, the lower copper vacancy concentration(x = 1/16) is able to enhance the absorption coefficient. The lower copper vacancy concentration(x = 1/16) is more favorable to improve the power factor in low or middle temperature. However, the high copper vacancy concentration(x = 1/4) is better in high temperature. These results give hints for the design of CuInTe2 as the good photovoltaic and thermoelectric materials.展开更多
As the featured material of the superionic thermoelectric(TE)material family,copper-chalcogenide Cu_(2-x)Se is attracting growing research interest for its excellent TE performance derived from the satisfactory power ...As the featured material of the superionic thermoelectric(TE)material family,copper-chalcogenide Cu_(2-x)Se is attracting growing research interest for its excellent TE performance derived from the satisfactory power factor and the ultra-low thermal conductivity induced by the superionic effect.Various efforts have been made and proved to be effective to further enhance the TE performance for Cu_(2-x)Se.However,this material is still far from the application stage,which is mainly due to concerns regarding control of the properties and the costly complex fabrication technology.Here we report a scalable pathway to achieve high-performance and tunable Cu_(2-x)Se,utilizing conventional sintering technology and copper(Cu)-vacancy engineering with an effective mass model.The figure of merit zT is a competitive value of 1.0 at 800 K for the optimized binary Cu_(2-x)Se,based on the precise modeling prediction and Cu-vacancy engineering.The changes in TE properties of Cu_(2-x)Se under heating-cooling cycle tests are also revealed.Our work offers the referable method along with the decent parent material for further enhancement of TE performance,paving a possible route for the application and industrialization of Cu_(2-x)Se TE materials.展开更多
基金supported by the National Natural Science Foundation of China(No.11747044)the Educational Commission of Hubei Province(No.B2018169)the Natural Science Foundation of Hubei Province(No.2017CFB526)
文摘The effects of copper-vacancy on the electrical, optical and thermoelectric properties of CuInTe2 have been investigated by the first-principles calculations and semi-classical Boltzmann theory. The estimated results of copper vacancy formation energies for Cu1-xn Te2(x = 0,1/16, 1/8 and 1/4) showed it is more difficult to prepare the sample with higher copper vacancy concentration. From the calculated energy band structures with MBJ-GGA, it can be seen that they are p-type semiconductors and the energy gap values increase with the vacancy concentration increasing. The wavelength is smaller than 460 nm, and the high copper vacancy concentration(x =1/4) is helpful to the values of absorption coefficient, while above 460 nm, the lower copper vacancy concentration(x = 1/16) is able to enhance the absorption coefficient. The lower copper vacancy concentration(x = 1/16) is more favorable to improve the power factor in low or middle temperature. However, the high copper vacancy concentration(x = 1/4) is better in high temperature. These results give hints for the design of CuInTe2 as the good photovoltaic and thermoelectric materials.
基金funded by The Hong Kong Polytechnic University[grant numbers 1-ZVGH,DD7F].
文摘As the featured material of the superionic thermoelectric(TE)material family,copper-chalcogenide Cu_(2-x)Se is attracting growing research interest for its excellent TE performance derived from the satisfactory power factor and the ultra-low thermal conductivity induced by the superionic effect.Various efforts have been made and proved to be effective to further enhance the TE performance for Cu_(2-x)Se.However,this material is still far from the application stage,which is mainly due to concerns regarding control of the properties and the costly complex fabrication technology.Here we report a scalable pathway to achieve high-performance and tunable Cu_(2-x)Se,utilizing conventional sintering technology and copper(Cu)-vacancy engineering with an effective mass model.The figure of merit zT is a competitive value of 1.0 at 800 K for the optimized binary Cu_(2-x)Se,based on the precise modeling prediction and Cu-vacancy engineering.The changes in TE properties of Cu_(2-x)Se under heating-cooling cycle tests are also revealed.Our work offers the referable method along with the decent parent material for further enhancement of TE performance,paving a possible route for the application and industrialization of Cu_(2-x)Se TE materials.
