Quantum Hall effect(QHE)in graphene has been widely studied due to its simple device architecture,modest cryogenic requirements,and the unique non-equidistant Landau-level spectrum of Dirac carriers.Real-space visuali...Quantum Hall effect(QHE)in graphene has been widely studied due to its simple device architecture,modest cryogenic requirements,and the unique non-equidistant Landau-level spectrum of Dirac carriers.Real-space visualization of the QHE in graphene is essential both for elucidating fundamental physics and for guiding graphene-based device design.Here,we present a novel scanning approach termed parallel EFM-sMIM imaging(PEMI)mode,which combines electrostatic force microscopy(EFM)and scanning microwave impedance microscopy(sMIM)to investigate the spatially distributed QHE in graphene.Comparative analysis reveals that the single-pass EFM mode demonstrates superior spatial resolution and signal-to-noise ratio compared to the constant-height EFM mode.PEMI measurements reveal that graphene’s electrical conductance manifests as discrete island-like domains exhibiting remarkable stability against magnetic field variations,and spatially distributed QHE states demonstrate independent emergence and evolution within these conductance islands.Notably,while tip-bias compensation demonstrates effectiveness in mitigating crosstalk interference,this technique inherently presents a trade-off by compromising the resolution of EFM signals.Finally,we employ contact-mode sMIM to measure carrier density and determine carrier type.This framework establishes a novel paradigm for parallel characterization of QHE textures and demonstrates promising extensibility to diverse 2D electronic systems through its adaptable architecture.展开更多
Solar cells featuring polythiophenes as donors are one of the optoelectronic devices that hold notable promises for commercial application,profiting from the lowest synthetic complexity and excellent scalability.Howev...Solar cells featuring polythiophenes as donors are one of the optoelectronic devices that hold notable promises for commercial application,profiting from the lowest synthetic complexity and excellent scalability.However,the complex phase behaviors of polythiophenes and their blends put constraints on modulating electrical performance and thus realizing stable performance under thermal stress.In this contribution,we present a multi-technique approach that combines calorimetry,scattering,spectroscopy,and microscopy to thoroughly probe the thermodynamic mixing,thermal properties of materials,the evolution of nanoscale domain structure,and device performance of poly(3-hexylthiophene)(P3HT)with a range of nonfullerene acceptors(NFAs)such as ITIC,IDTBR,and ZY-4Cl.Accordingly,two blending guidelines are established for matching these popular NFAs with P3HT to enable highly efficient and thermally stable cells.First,blend systems with weak vitrification and hypo-miscibility are excellent candidates for efficient solar cells.Furthermore,high thermal stability can be achieved by selecting NFAs with diffusion-limited crystallization.The P3HT:ZY-4Cl blend was found to endow the best performance of over 10%efficiency and an exceptionally high T_(80) lifetime of>6000 h under continuous thermal annealing,which are among the highest values for P3HT-based solar cells.This realization of high thermal stability and efficiency demonstrates the remarkable potentials of simple polythiophene:nonfullerene pairs in electronic applications.展开更多
基金funded by the National Natural Science Foundation of China(Nos.12374199,62488201,92477128)the Beijing Nova Program(No.20240484651)the China Postdoctoral Science Foundation(Nos.2025M773341,GZC20252200).
文摘Quantum Hall effect(QHE)in graphene has been widely studied due to its simple device architecture,modest cryogenic requirements,and the unique non-equidistant Landau-level spectrum of Dirac carriers.Real-space visualization of the QHE in graphene is essential both for elucidating fundamental physics and for guiding graphene-based device design.Here,we present a novel scanning approach termed parallel EFM-sMIM imaging(PEMI)mode,which combines electrostatic force microscopy(EFM)and scanning microwave impedance microscopy(sMIM)to investigate the spatially distributed QHE in graphene.Comparative analysis reveals that the single-pass EFM mode demonstrates superior spatial resolution and signal-to-noise ratio compared to the constant-height EFM mode.PEMI measurements reveal that graphene’s electrical conductance manifests as discrete island-like domains exhibiting remarkable stability against magnetic field variations,and spatially distributed QHE states demonstrate independent emergence and evolution within these conductance islands.Notably,while tip-bias compensation demonstrates effectiveness in mitigating crosstalk interference,this technique inherently presents a trade-off by compromising the resolution of EFM signals.Finally,we employ contact-mode sMIM to measure carrier density and determine carrier type.This framework establishes a novel paradigm for parallel characterization of QHE textures and demonstrates promising extensibility to diverse 2D electronic systems through its adaptable architecture.
基金National Natural Science Foundation of China,Grant/Award Number:52073207Special Fund for Graduate Education of Tianjin University,Grant/Award Number:C1-2021-008。
文摘Solar cells featuring polythiophenes as donors are one of the optoelectronic devices that hold notable promises for commercial application,profiting from the lowest synthetic complexity and excellent scalability.However,the complex phase behaviors of polythiophenes and their blends put constraints on modulating electrical performance and thus realizing stable performance under thermal stress.In this contribution,we present a multi-technique approach that combines calorimetry,scattering,spectroscopy,and microscopy to thoroughly probe the thermodynamic mixing,thermal properties of materials,the evolution of nanoscale domain structure,and device performance of poly(3-hexylthiophene)(P3HT)with a range of nonfullerene acceptors(NFAs)such as ITIC,IDTBR,and ZY-4Cl.Accordingly,two blending guidelines are established for matching these popular NFAs with P3HT to enable highly efficient and thermally stable cells.First,blend systems with weak vitrification and hypo-miscibility are excellent candidates for efficient solar cells.Furthermore,high thermal stability can be achieved by selecting NFAs with diffusion-limited crystallization.The P3HT:ZY-4Cl blend was found to endow the best performance of over 10%efficiency and an exceptionally high T_(80) lifetime of>6000 h under continuous thermal annealing,which are among the highest values for P3HT-based solar cells.This realization of high thermal stability and efficiency demonstrates the remarkable potentials of simple polythiophene:nonfullerene pairs in electronic applications.
