Abstract Two‐dimensional (2D) tellurene (Te) has shown its great potential in nanoelectronics for its high carrier mobility and air stability. However, the high‐resistance electrical contact and relatively thick Te channel hinder its ultimate scaling and device performance. Here, the transport property of Te field‐effect transistors using platinum (Pt) contact with high work function is studied, which facilitates the effective hole injection in the p‐type Te channel. The electrical contact to Te using the Y‐function method (YFM) and the transmission line method (TLM) is investigated. The Te transistors with Pt contact show a low contact resistance of 400 Ωµm, a short transfer length of 80 nm, and low specific contact resistivity of 3.2 × 10 −7 Ωcm 2 , resulting from the low Schottky barrier height (SBH) of Pt/Te interface. The Pt electrode also can work as an efficient catalyst that allows reduction of the Te channel thickness with a controllable thinning process in water under white light illumination. This self‐aligned catalytic thinning process enables the construction of the transistors with a thin Te channel and thick Te contact with Pt metal electrodes, which provides a device configuration with both effective electrostatic control and low contact resistance.
The specific capacitance of NCA 15 -MOF/NF was 1317 F g −1 , which was significantly higher compared to the NCA 0 -MOF/NF. After 15 000 charge–discharge cycles, the NCA 15 -MOF/NF retained 89% of its initial specific capacitance.
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
Abstract Regulating molecular packing and aggregation of photoactive layer is a critical but challenging issue in developing high‐performance organic solar cells. Herein, two structurally similar analogues of anthra[2,3‐ b : 6,7‐ b ′]dithiophene (ADT) and naphtho[1,2‐ b : 5,6‐ b ′]dithiophene (NDT) are developed as solid additive to exploit their effect in regulating the molecular aggregation and π‐stacking of photoactive layer. We clarify that the perpendicular arrangements of NDT can enlarge the molecular packing space and improve the face‐on stacking of Y6 during the film formation, favoring a more compact and ordered long‐range π‐π stacking in the out‐of‐plane direction after the removal of NDT under thermal annealing. The edge‐to‐face stacked herringbone‐arrangement of ADT along with its non‐volatilization under thermal annealing can induce the coexistence of face‐on and edge‐on stacking of blend film. As a result, the NDT treatment shows encouraging effect in improving the photovoltaic performance of devices based on various systems. Particularly, a remarkable PCE of 18.85 % is achieved in the PM6 : L8‐BO‐based device treated by NDT additive, which is a significant improvement with regard to the PCE of 16.41 % for the control device. This work offers a promising strategy to regulate the molecular packing and aggregation of photoactive layer towards significantly improved performance and stability of organic solar cells.
Abstract The quasimetallic 1T′ phase 2D transition‐metal dichalcogenides (TMDs) consist of 1D zigzag metal chains stacked periodically along a single axis. This gives rise to its prominent physical properties which promises the onset of novel physical phenomena and applications. Here, the in‐plane electronic correlations are explored, and new mid‐infrared plasmon excitations in 1T′ phase monolayer WSe 2 and MoS 2 are observed using optical spectroscopies. Based on an extensive first‐principles study which analyzes the charge dynamics across multiple axes of the atomic‐layered systems, the collective charge excitations are found to disperse only along the direction perpendicular to the chains. Further analysis reveals that the interchain long‐range coupling is responsible for the coherent 1D charge dynamics and the spin–orbit coupling affects the plasmon frequency. Detailed investigation of these charge collective modes in 2D‐chained systems offers opportunities for novel device applications and has implications for the underlying mechanism that governs superconductivity in 2D TMD systems.
Two-dimensional (2D) layered materials, transition metal dichalcogenides and black phosphorus, have attracted much interest from the viewpoints of fundamental physics and device applications. The establishment of new functionalities in anisotropic layered 2D materials is a challenging but rewarding frontier, owing to their remarkable optical properties and prospects for new devices. Here, we report the anisotropic optical properties of layered 2D monochalcogenide of germanium sulfide (GeS). Three Raman scattering peaks corresponding to the B3g, A1g, and A2g modes with strong polarization dependence are demonstrated in the GeS flakes, which validates polarized Raman spectroscopy as an effective method for identifying the crystal orientation of anisotropic layered GeS. Photoluminescence (PL) is observed with a peak at around 1.66 eV that originates from the direct optical transition in GeS at room temperature. Moreover, determination of the polarization dependent characteristics of the PL and absorption reveals an anisotropic optical transition near the band edge of GeS, which is also supported by the density functional theory calculations. This anisotropic layered GeS presents the opportunities for the discovery of new physical phenomena and will find applications that exploit its anisotropic properties.
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