Metal-organic frameworks(MOFs),which comprise metal cations and organic ligands connected through coordination bonds,exhibit exceptional porosity and tunable properties,making them promising for thermoelectric applica...Metal-organic frameworks(MOFs),which comprise metal cations and organic ligands connected through coordination bonds,exhibit exceptional porosity and tunable properties,making them promising for thermoelectric applications.However,most MOFs have low electrical conductivity,which limits their application in thermoelectric devices.Doping transition metal ions into MOF systems can provide adequate conductivity for thermoelectric conversion.Thus,in this study,the thermoelectric properties of Cu-doped nickel benzene-1,3,5-tricarboxylate(NiBTC)were investigated to optimize its carrier concentration and mobility.NiBTC was synthesized into a hollow structure to enhance its phonon scattering and then doped with copper to tune its electrical conductivity and Seebeck coefficient.The synthesis was confirmed through various characterization techniques,including XRD,FTIR spectroscopy,and electron microscopy.Cu doping significantly increased its electrical conductivity by~10%while slightly decreasing its Seebeck coefficient;however,high doping levels(15%)resulted in a CuBTC byproduct,which negatively affected its performance.The findings revealed that the substitution of Ni^(2+)with Cu^(2+)enhances its electrical performance by improving its carrier concentration and mobility,while the hollow structure reduces its thermal conductivity.The optimized Cu-NiBTC composite exhibited promising thermoelectric performance,with a maximum figure of merit of 0.571 at 473 K.This study highlights the potential of MOF-based composites for thermoelectric applications,promoting future advancements in energy-harvesting technologies.展开更多
The state of polarization(SOP)on high-order Poincaréspheres(HOPSs),characterized by their distinctive phase profiles and polarization distributions,plays a crucial role in both classical and quantum optical appli...The state of polarization(SOP)on high-order Poincaréspheres(HOPSs),characterized by their distinctive phase profiles and polarization distributions,plays a crucial role in both classical and quantum optical applications.However,most existing metasurface-based implementations face inherent limitations:passive designs are restricted to represent a few predefined HOPS SOPs,while programmable versions typically constrain to 1-bit or 2-bit phase control resolution.In this paper,dynamic generation of HOPS beams with arbitrary SOP based on a transmissive space-time-coding metasurface is demonstrated.By combining 1-bit phase discretizations via PIN diodes with a time-coding strategy,the metasurface enables quasi-continuous complexamplitude modulation for harmonic waves in both x-and y-polarizations.Based on near-field diffraction theory,arbitrary SOPs on any HOPSm,n can be precisely generated using a linearly polarized basis,which is independently controlled by FPGA reconfiguration.We experimentally demonstrate that polarization holography on HOPS0,0 achieves high polarization purity>91.28%,and vector vortex beams on HOPS1,3 and HOPS−1,3 exhibit high orbital angular momentum mode purities>91.25%.This methodology holds great potential for structured wavefront shaping,vortex generation,and high-capacity planar photonics.展开更多
基金funded and conducted under the Competency Development Program for Industry Specialists of the Korean Ministry of Trade,Industry and Energy(MOTIE),operated by Korea Institute for Advancement of Technology(KIAT),(No.P0012453,Next-generation Display Expert Training Project for Innovation Process)supported by Korea Institute of Energy Technology Evaluation and Planning(KETEP)grant funded by the Korea government(MOTIE)(No.RS 2024-00398346,ESS BigData-Based O&M and Asset Management Technical Manpower Training).
文摘Metal-organic frameworks(MOFs),which comprise metal cations and organic ligands connected through coordination bonds,exhibit exceptional porosity and tunable properties,making them promising for thermoelectric applications.However,most MOFs have low electrical conductivity,which limits their application in thermoelectric devices.Doping transition metal ions into MOF systems can provide adequate conductivity for thermoelectric conversion.Thus,in this study,the thermoelectric properties of Cu-doped nickel benzene-1,3,5-tricarboxylate(NiBTC)were investigated to optimize its carrier concentration and mobility.NiBTC was synthesized into a hollow structure to enhance its phonon scattering and then doped with copper to tune its electrical conductivity and Seebeck coefficient.The synthesis was confirmed through various characterization techniques,including XRD,FTIR spectroscopy,and electron microscopy.Cu doping significantly increased its electrical conductivity by~10%while slightly decreasing its Seebeck coefficient;however,high doping levels(15%)resulted in a CuBTC byproduct,which negatively affected its performance.The findings revealed that the substitution of Ni^(2+)with Cu^(2+)enhances its electrical performance by improving its carrier concentration and mobility,while the hollow structure reduces its thermal conductivity.The optimized Cu-NiBTC composite exhibited promising thermoelectric performance,with a maximum figure of merit of 0.571 at 473 K.This study highlights the potential of MOF-based composites for thermoelectric applications,promoting future advancements in energy-harvesting technologies.
基金National Natural Science Foundation of China(62271056,62171186,62201037)Technology Innovation Center of Infrared Remote Sensing Metrology Technology of State Administration for Market Regulation(AKYKF2423)+5 种基金National Key Research and Development Program of China(2022YFF0604801)Beijing Natural Science Foundation Haidian Original Innovation Joint Fund(L222042)Open Research Fund of State Key Laboratory of Millimeter Waves(K202326)Open Research Fund of State Key Laboratory of Space-Ground Integrated Information Technology(6142221200201)Basic Research Foundation of Beijing Institute of Technology,China(BITBLR2020014)111 Project of China(B14010).
文摘The state of polarization(SOP)on high-order Poincaréspheres(HOPSs),characterized by their distinctive phase profiles and polarization distributions,plays a crucial role in both classical and quantum optical applications.However,most existing metasurface-based implementations face inherent limitations:passive designs are restricted to represent a few predefined HOPS SOPs,while programmable versions typically constrain to 1-bit or 2-bit phase control resolution.In this paper,dynamic generation of HOPS beams with arbitrary SOP based on a transmissive space-time-coding metasurface is demonstrated.By combining 1-bit phase discretizations via PIN diodes with a time-coding strategy,the metasurface enables quasi-continuous complexamplitude modulation for harmonic waves in both x-and y-polarizations.Based on near-field diffraction theory,arbitrary SOPs on any HOPSm,n can be precisely generated using a linearly polarized basis,which is independently controlled by FPGA reconfiguration.We experimentally demonstrate that polarization holography on HOPS0,0 achieves high polarization purity>91.28%,and vector vortex beams on HOPS1,3 and HOPS−1,3 exhibit high orbital angular momentum mode purities>91.25%.This methodology holds great potential for structured wavefront shaping,vortex generation,and high-capacity planar photonics.
