CIGS thin films are deposited by sputtering and selenization, The synthesis of semiconducting polycrystalline thin films and characteristics of devices based on the CIGS absorbing layers are investigated. Their micros...CIGS thin films are deposited by sputtering and selenization, The synthesis of semiconducting polycrystalline thin films and characteristics of devices based on the CIGS absorbing layers are investigated. Their microstructures are characterized by x-ray diffraction and Raman spectroscopy, The results reveal that there exist metallic Cu2-xSe compounds in CIGS film surfaces and the compounds are thought to be responsible for the degradation of the open circuit voltage of solar cells. The optimization of selenization temperature profile and copper content in the precursor surfaces is studied, concluding that the conversion efficiency may be improved by removing metallic Cu2-xSe compounds from the surfaces of CIGS thin films.展开更多
The temperature dependences of upper critical field(Hc2) for a series of iron-deficient Fe1-xSe single crystals are obtained from the measurements of in-plane resistivity in magnetic fields up to 9 T and perpendicular...The temperature dependences of upper critical field(Hc2) for a series of iron-deficient Fe1-xSe single crystals are obtained from the measurements of in-plane resistivity in magnetic fields up to 9 T and perpendicular to the ab plane. For the samples with lower superconducting transition temperature Tc(< 7.2 K), the temperature dependence of Hc2 is appropriately described by an effective two-band model. For the samples with higher Tc( 7.2 K), the temperature dependence can also be fitted by a single-band Werthamer–Helfand–Hohenberg formula, besides the two-band model. Such a Tc-dependent change in Hc2(T) behavior is discussed in connection with recent related experimental results, showing an inherent link between the changes of intrinsic superconducting and normal state properties in the Fe Se system.展开更多
Transition metal dichalcogenides have shown promise as highly efficient hydrogen evolution reaction(HER)electrocatalysts.In this work,we demonstrate a one-pot hydrothermal synthesis of ternary 2H-MoS_(2)xSe_(2(1−x))na...Transition metal dichalcogenides have shown promise as highly efficient hydrogen evolution reaction(HER)electrocatalysts.In this work,we demonstrate a one-pot hydrothermal synthesis of ternary 2H-MoS_(2)xSe_(2(1−x))nanosheets for enhanced hydrogen production.Compared to pristine 2H-MoSe_(2)and 2H-MoS_(2),introduction of a third element not only expands the interlayer spacing,but also provides more active catalytic sites and lowers the charge transfer resistance.As a consequence,MoS_(2)xSe_(2(1−x))exhibits a high electrocatalytic HER activity with a low overpotential of 188 mV vs.a RHE to achieve a geometric current density of−10 mA cm^(−2)and a low Tafel slope of 43 mV dec^(−1 )in 0.5 M H_(2)SO_(4).This study provides valuable insights that ternary structure formation can be effective for the preparation of high-performance HER electrocatalysts.展开更多
文摘CIGS thin films are deposited by sputtering and selenization, The synthesis of semiconducting polycrystalline thin films and characteristics of devices based on the CIGS absorbing layers are investigated. Their microstructures are characterized by x-ray diffraction and Raman spectroscopy, The results reveal that there exist metallic Cu2-xSe compounds in CIGS film surfaces and the compounds are thought to be responsible for the degradation of the open circuit voltage of solar cells. The optimization of selenization temperature profile and copper content in the precursor surfaces is studied, concluding that the conversion efficiency may be improved by removing metallic Cu2-xSe compounds from the surfaces of CIGS thin films.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11888101 and 11834016)the National Key Research and Development Program of China(Grant Nos.2017YFA0303003 and 2016YFA0300300)the Strategic Priority Research Program and Key Research Program of Frontier Sciences of the Chinese Academy of Sciences(Grant Nos.QYZDY-SSW-SLH001 and XDB25000000)
文摘The temperature dependences of upper critical field(Hc2) for a series of iron-deficient Fe1-xSe single crystals are obtained from the measurements of in-plane resistivity in magnetic fields up to 9 T and perpendicular to the ab plane. For the samples with lower superconducting transition temperature Tc(< 7.2 K), the temperature dependence of Hc2 is appropriately described by an effective two-band model. For the samples with higher Tc( 7.2 K), the temperature dependence can also be fitted by a single-band Werthamer–Helfand–Hohenberg formula, besides the two-band model. Such a Tc-dependent change in Hc2(T) behavior is discussed in connection with recent related experimental results, showing an inherent link between the changes of intrinsic superconducting and normal state properties in the Fe Se system.
基金supported by the National Natural Science Foundation of China(grant no.21471039,21571043,21671047)the Fundamental Research Funds for the Central Universities(PIRS of HIT A201502 and HIT.BRETIII.201223)+2 种基金the China Postdoctoral Science Foundation(2014M560253)the Postdoctoral Scientific Research Fund of Heilongjiang Province(LBH-Q14062,LBH-Z14076)the Natural Science Foundation of Heilongjiang Province(B2015001).
文摘Transition metal dichalcogenides have shown promise as highly efficient hydrogen evolution reaction(HER)electrocatalysts.In this work,we demonstrate a one-pot hydrothermal synthesis of ternary 2H-MoS_(2)xSe_(2(1−x))nanosheets for enhanced hydrogen production.Compared to pristine 2H-MoSe_(2)and 2H-MoS_(2),introduction of a third element not only expands the interlayer spacing,but also provides more active catalytic sites and lowers the charge transfer resistance.As a consequence,MoS_(2)xSe_(2(1−x))exhibits a high electrocatalytic HER activity with a low overpotential of 188 mV vs.a RHE to achieve a geometric current density of−10 mA cm^(−2)and a low Tafel slope of 43 mV dec^(−1 )in 0.5 M H_(2)SO_(4).This study provides valuable insights that ternary structure formation can be effective for the preparation of high-performance HER electrocatalysts.
