The coupling between electrons and phonons is ubiquitous in condensed matter physics. In recent years, with the rise of two dimensional (2D) materials, electron–phonon interaction exhibits unique characteristics compared with their three‐dimensional counterparts. In this paper, research progress of electron–phonon interaction in 2D materials is briefly reviewed, mainly focus on thermoelectric device, conventional superconductor, field effect transistor, and photoelectric device. Firstly, electron–phonon interaction on thermoelectric application of 2D materials is concluded according to recent reports, and strategies to increase figure of merit are discussed. Next, strong electron–phonon coupling strength is essential for increasing transition temperature of superconductors. Conversely, electron–phonon interaction inhibits the carrier mobility for transport process. By summarizing research works in the past years, its role on the performance of 2D materials‐based field effect transistors is fully evaluated. Furthermore, the influences of electron–phonon interaction on light–matter interaction in 2D materials are briefly overviewed. Finally, some outlooks in the field are prospected. In a word, understanding electron–phonon interaction in 2D materials establishes strategically important directions for manipulating physical properties and optimizing device design.
Transition metal sulfide has been regarded as an ideal electrode material for supercapacitors due to its high energy density. However, the poor cyclic stability caused by low electroconductivity seriously limits its practical application. Herein, carbon nanotubes and nickel−cobalt bimetallic organic framework composites were prepared by the in situ growth method and used as precursors to prepare carbon nanotubes/nickel−cobalt bimetallic sulfide (CNTs/ Ni−Co−S-3) composites. Benefits from the synergy between the components, CNTs/Ni−Co−S-3, as a positive electrode material, presented an extremely high specific capacity of 734 C g −1 at 1 A g −1 and an improved rate capability. Furthermore, when CNTs/Ni− Co−S served as the positive electrode of the hybrid supercapacitor (CNTs/Ni−Co−S-3//AC HSC), the device provided a competitive energy density of 42.15 Wh kg −1 at the power density of 852 W kg −1 and long-term stability (88.46% of specific capacitance retention for 10000 cycles at 8 A g −1 ). This synthesis strategy provides a new pathway for further improving the energy density and cyclic stability of metallic sulfide group composite electrodes.
Photocarrier dynamics including interlayer charge transfer and intralayer valley scattering are studied in a heterostructure formed by trilayers of WS2 and MoSe2. The sample is fabricated by mechanical exfoliation and...
In recent years, van der Waals heterostructures (vdWHs) of two-dimensional (2D) materials have attracted extensive research interest. By stacking various 2D materials together to form vdWHs, it is interesting to see that new and fascinating properties are formed beyond single 2D materials; thus, 2D heterostructures-based nanodevices, especially for potential optoelectronic applications, were successfully constructed in the past few decades. With the dramatically increased demand for well-controlled heterostructures for nanodevices with desired performance in recent years, various interfacial modulation methods have been carried out to regulate the interfacial coupling of such heterostructures. Here, the research progress in the study of interfacial coupling of vdWHs (investigated by Photoluminescence, Raman, and Pump–probe spectroscopies as well as other techniques), the modulation of interfacial coupling by applying various external fields (including electrical, optical, mechanical fields), as well as the related applications for future electrics and optoelectronics, have been briefly reviewed. By summarizing the recent progress, discussing the recent advances, and looking forward to future trends and existing challenges, this review is aimed at providing an overall picture of the importance of interfacial modulation in vdWHs for possible strategies to optimize the device’s performance.
Negative capacitance (NC) in dye-sensitized solar cells (DSCs) has been confirmed experimentally. In this work, the recombination behavior of carriers in DSC with semiconductor interface as a carrier's transport layer is explored theoretically in detail. Analytical results indicate that the recombination behavior of carriers could contribute to the NC of DSCs under small signal perturbation. Using this recombination capacitance we propose a novel equivalent circuit to completely explain the negative terminal capacitance. Further analysis based on the recombination complex impedance show that the NC is inversely proportional to frequency. In addition, analytical recombination resistance is composed by the alternating current (AC) recombination resistance (R rac ) and the direct current (DC) recombination resistance (R rdc ), which are caused by small-signal perturbation and the DC bias voltage, respectively. Both of two parts will decrease with increasing bias voltage.
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