Two-dimensional(2D)thermoelectric(TE)materials have been widely developed;however,some 2D materials exhibit isotropic phonon,electron transport properties,and poor TE performance,which limit their application scope.Th...Two-dimensional(2D)thermoelectric(TE)materials have been widely developed;however,some 2D materials exhibit isotropic phonon,electron transport properties,and poor TE performance,which limit their application scope.Thus,exploring excellent anisotropic and ultrahigh-performance TE materials are very warranted.Herein,we first investigate the phonon thermal and TE properties of a novel 2D-connectivity ternary compound named Ga2I2S2.This paper comprehensively studies the phonon dispersion,phonon anharmonicity,lattice thermal conductivity,electronic structure,carrier mobility,Seebeck coefficient,electrical conductivity,and the dimensionless figure of merit(ZT)versus carrier concentration for 2D Ga_(2)I_(2)S_(2).We conclude that the in-plane lattice thermal conductivities of Ga_(2)I_(2)S_(2) at room temperature(300 K)are found to be 1.55 W mK^(−1) in the X-axis direction(xx-direction)and 3.82 W mK^(−1)in the Y-axis direction(yy-direction),which means its anisotropy ratio reaches 1.46.Simultaneously,the TE performance of p-type and n-type doping 2D Ga2I2S2 also shows significant anisotropy,giving rise to the ZT peak values of p-type doping in xx-and yy-directions being 0.81 and 1.99,respectively,and those of n-type doping reach ultrahigh values of 7.12 and 2.89 at 300 K,which are obviously higher than the reported values for p-type and n-type doping ternary compound Sn2BiX(ZT∼1.70 and∼2.45 at 300 K)(2020 Nano Energy 67104283).This work demonstrates that 2D Ga_(2)I_(2)S_(2) has high anisotropic TE conversion efficiency and can also be used as a new potential room-temperature TE material.展开更多
The van der Waals(vdW)heterostructures of bilayer transition metal dichalcogenide obtained by vertically stacking have drawn increasing attention for their enormous potential applications in semiconductors and insulat...The van der Waals(vdW)heterostructures of bilayer transition metal dichalcogenide obtained by vertically stacking have drawn increasing attention for their enormous potential applications in semiconductors and insulators.Here,by using the first-principles calculations and the phonon Boltzmann transport equation(BTE),we studied the phonon transport properties of WS2/WSe2 bilayer heterostructures(WS2/WSe2-BHs).The lattice thermal conductivity of the ideal WS2/WSe2-BHs crystals at room temperature(RT)was 62.98 W/mK,which was clearly lower than the average lattice thermal conductivity of WS2 and WSe2 single layers.Another interesting finding is that the optical branches below 4.73 THz and acoustic branches have powerful coupling,mainly dominating the lattice thermal conductivity.Further,we also noticed that the phonon mean free path(MFP)of the WS2/WSe2-BHs(233 nm)was remarkably attenuated by the free-standing monolayer WS2(526 nm)and WSe2(1720 nm),leading to a small significant size effect of the WS2/WSe2-BHs.Our results systematically demonstrate the low optical and acoustic phonon modes-dominated phonon thermal transport in heterostructures and give a few important guidelines for the synthesis of van der Waals heterostructures with excellent phonon transport properties.展开更多
Phage display technology is a unique gene recombination expression technology, and it is also a simple and effective screening tool. Through panning, a protein or peptide with high affinity and selectivity to the targ...Phage display technology is a unique gene recombination expression technology, and it is also a simple and effective screening tool. Through panning, a protein or peptide with high affinity and selectivity to the target is obtained. Antibody phage display has become the first and most widely used <i><span style="font-family:Verdana;">in vitro</span></i><span style="font-family:Verdana;"> screening technology. Phage display derivatives play an important role in the diagnosis and treatment of diseases. This article reviews the phage display system of phage display technology, the size and classification of antibody libraries and their applications, and discusses the application prospects and challenges of phage display technology.</span><span style="font-family:Verdana;"> </span><span style="font-family:Verdana;">This thesis lays the foundation for the theoretical and experimental research of bacteriophages.</span>展开更多
High-pressure has been widely utilized to improve material performances such as thermal conductiv-ityκand interfacial thermal conductance G.Gallium arsenide(GaAs)as a functional semiconductor has attracted extensive ...High-pressure has been widely utilized to improve material performances such as thermal conductiv-ityκand interfacial thermal conductance G.Gallium arsenide(GaAs)as a functional semiconductor has attracted extensive attention in high-pressure studies for its technological importance and complex structure transitions.Thermal properties of GaAs under high pressure are urgent needs in physics but remain elusive.Herein,we systematically investigateκGaAs and G Al/GaAs of multi-structure up to -23 GPa.We conclude that:(1)in pressurization,phonon group velocity,lattice defects,and electrons play a central role inκGaAs in elastic,plastic,and metallization regions,respectively.The increased phonon density of states(PDOS)overlap,group velocity,and interfacial bonding enhances G Al/GaAs.(2)In depressurization,electrons remain the dominant factor on κ GaAs from 23 to 13.5 GPa.G Al/GaAs increases dramatically at -12 GPa due to the larger PDOS overlap.With decompressing to ambient,lattice defects including grain size reduction,arsenic vacancies,and partial amorphization reduce κ GaAs to a glass-like value.Remarkably,the released G Al/GaAs is 2.6 times higher than that of the initial.Thus our findings open a new dimension in synergistically realizing glass-like κ and enhancing G,which can facilitate thermoelectric performance and its potential engineering applications.展开更多
基金support from the National Natural Science Foundation of China[51720105007,52076031,11602149,51806031,52176166]the Fundamental Research Funds for the Central Universities[DUT19RC(3)006]the computing resources from the Supercomputer Center of Dalian University of Technology and RWTH Aachen University under project 3357.
文摘Two-dimensional(2D)thermoelectric(TE)materials have been widely developed;however,some 2D materials exhibit isotropic phonon,electron transport properties,and poor TE performance,which limit their application scope.Thus,exploring excellent anisotropic and ultrahigh-performance TE materials are very warranted.Herein,we first investigate the phonon thermal and TE properties of a novel 2D-connectivity ternary compound named Ga2I2S2.This paper comprehensively studies the phonon dispersion,phonon anharmonicity,lattice thermal conductivity,electronic structure,carrier mobility,Seebeck coefficient,electrical conductivity,and the dimensionless figure of merit(ZT)versus carrier concentration for 2D Ga_(2)I_(2)S_(2).We conclude that the in-plane lattice thermal conductivities of Ga_(2)I_(2)S_(2) at room temperature(300 K)are found to be 1.55 W mK^(−1) in the X-axis direction(xx-direction)and 3.82 W mK^(−1)in the Y-axis direction(yy-direction),which means its anisotropy ratio reaches 1.46.Simultaneously,the TE performance of p-type and n-type doping 2D Ga2I2S2 also shows significant anisotropy,giving rise to the ZT peak values of p-type doping in xx-and yy-directions being 0.81 and 1.99,respectively,and those of n-type doping reach ultrahigh values of 7.12 and 2.89 at 300 K,which are obviously higher than the reported values for p-type and n-type doping ternary compound Sn2BiX(ZT∼1.70 and∼2.45 at 300 K)(2020 Nano Energy 67104283).This work demonstrates that 2D Ga_(2)I_(2)S_(2) has high anisotropic TE conversion efficiency and can also be used as a new potential room-temperature TE material.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.51720105007,51806031,11602149,and GZ1257)the Fundamental Research Funds for the Central Universities,China(Grant Nos.DUT16RC(3)116 and DUT19RC(3)006)The computing resources from Supercomputer Center of Dalian University of Technology and ScGrid are greatly acknowledged。
文摘The van der Waals(vdW)heterostructures of bilayer transition metal dichalcogenide obtained by vertically stacking have drawn increasing attention for their enormous potential applications in semiconductors and insulators.Here,by using the first-principles calculations and the phonon Boltzmann transport equation(BTE),we studied the phonon transport properties of WS2/WSe2 bilayer heterostructures(WS2/WSe2-BHs).The lattice thermal conductivity of the ideal WS2/WSe2-BHs crystals at room temperature(RT)was 62.98 W/mK,which was clearly lower than the average lattice thermal conductivity of WS2 and WSe2 single layers.Another interesting finding is that the optical branches below 4.73 THz and acoustic branches have powerful coupling,mainly dominating the lattice thermal conductivity.Further,we also noticed that the phonon mean free path(MFP)of the WS2/WSe2-BHs(233 nm)was remarkably attenuated by the free-standing monolayer WS2(526 nm)and WSe2(1720 nm),leading to a small significant size effect of the WS2/WSe2-BHs.Our results systematically demonstrate the low optical and acoustic phonon modes-dominated phonon thermal transport in heterostructures and give a few important guidelines for the synthesis of van der Waals heterostructures with excellent phonon transport properties.
文摘Phage display technology is a unique gene recombination expression technology, and it is also a simple and effective screening tool. Through panning, a protein or peptide with high affinity and selectivity to the target is obtained. Antibody phage display has become the first and most widely used <i><span style="font-family:Verdana;">in vitro</span></i><span style="font-family:Verdana;"> screening technology. Phage display derivatives play an important role in the diagnosis and treatment of diseases. This article reviews the phage display system of phage display technology, the size and classification of antibody libraries and their applications, and discusses the application prospects and challenges of phage display technology.</span><span style="font-family:Verdana;"> </span><span style="font-family:Verdana;">This thesis lays the foundation for the theoretical and experimental research of bacteriophages.</span>
基金financially supported by the National Natural Science Foundation of China(Nos.51720105007,51976025,and 52206219)the Fundamental Research Funds for the Central Universities(No.DUT22ZD216).
文摘High-pressure has been widely utilized to improve material performances such as thermal conductiv-ityκand interfacial thermal conductance G.Gallium arsenide(GaAs)as a functional semiconductor has attracted extensive attention in high-pressure studies for its technological importance and complex structure transitions.Thermal properties of GaAs under high pressure are urgent needs in physics but remain elusive.Herein,we systematically investigateκGaAs and G Al/GaAs of multi-structure up to -23 GPa.We conclude that:(1)in pressurization,phonon group velocity,lattice defects,and electrons play a central role inκGaAs in elastic,plastic,and metallization regions,respectively.The increased phonon density of states(PDOS)overlap,group velocity,and interfacial bonding enhances G Al/GaAs.(2)In depressurization,electrons remain the dominant factor on κ GaAs from 23 to 13.5 GPa.G Al/GaAs increases dramatically at -12 GPa due to the larger PDOS overlap.With decompressing to ambient,lattice defects including grain size reduction,arsenic vacancies,and partial amorphization reduce κ GaAs to a glass-like value.Remarkably,the released G Al/GaAs is 2.6 times higher than that of the initial.Thus our findings open a new dimension in synergistically realizing glass-like κ and enhancing G,which can facilitate thermoelectric performance and its potential engineering applications.