Electronic and optical properties of 3N-doped graphdiyne/MoS_(2) heterostructures tuned by biaxial strain and external electric field

The construction of van der Waals(vdW)heterostructures by stacking different two-dimensional layered materials have been recognised as an effective strategy to obtain the desired properties.The 3N-doped graphdiyne(N-GY)has been successfully synthesized in the laboratory.It could be assembled into a supercapacitor and can be used for tensile energy storage.However,the flat band and wide forbidden bands could hinder its application of N-GY layer in optoelectronic and nanoelectronic devices.In order to extend the application of N-GY layer in electronic devices,MoS_(2) was selected to construct an N-GY/MoS_(2) heterostructure due to its good electronic and optical properties.The N-GY/MoS_(2) heterostructure has an optical absorption range from the visible to ultraviolet with a absorption coefficient of 10^(5) cm^(-1).The N-GY/MoS_(2) heterostructure exhibits a type-II band alignment allows the electron–hole to be located on N-GY and MoS_(2) respectively,which can further reduce the electron–hole complexation to increase exciton lifetime.The power conversion efficiency of N-GY/MoS_(2) heterostructure is up to 17.77%,indicating it is a promising candidate material for solar cells.In addition,the external electric field and biaxial strain could effectively tune the electronic structure.Our results provide a theoretical support for the design and application of N-GY/MoS_(2) vdW heterostructures in semiconductor sensors and photovoltaic devices.

Construction and nanotribological study of a glassy covalent organic network on surface

Unraveling the nature of complex condensed matter systems is of paramount importance in a variety of fields such as pharmacology and materials science.Here we report the synthesis,by the dynamic covalent chemistry(DCC),of a robust,continuous,and low-defect glassy covalent organic network(GCON).The direct imaging of the molecular structure clearly shows the amorphous nature of GCONs,which consists with the competing(nano)crystallite model,not Zachariasen continuous random networks(Z-CRN).Remarkably,the microscopic friction properties were measured on GCONs by atomic force microscopy(AFM),and the GCONs showed lower friction force in comparison with crystalline covalent organic frameworks(COFs).

2D-polyimide film sensitized monolayer MoS_(2) phototransistor enabled near-infrared photodetection

Two-dimensional(2D)transition metal dichalcogenides(TMDCs)-based heterostructures open the door to fabricate various promising hybrid photodetectors,while it is still a challenge to achieve excellent and stable near-infrared(NIR)photoresponse.Here,a MoS_(2)–2DPI(2D-polyimide(2DPI))heterojunction-based phototransistor(HPT)was fabricated.Near-infrared photodetection with excellent performance has been realized.This HPT exhibited a photoresponsivity of 390.5 A/W,a specific detectivity of 5.10×10^(12)Jones,a photogain 1.04×10^(5),and a photoresponse rise and decay time of 400 and 430 ms(λ=900 nm,P=16.2μW/cm^(2)),respectively.It also shows a broadband wavelength response from 405 to 1,020 nm.This superior performance could be attributed to the strong near-infrared absorption and the type-II(staggered)band alignment which ensures efficient charge transfer from 2DPI to MoS_(2).The face-to-face spatial configuration of MoS_(2)–2DPI heterostructures ensures efficient transfer of photoinduced carriers through the interface,electron and holes can be separated due to the large band offsets.This work presents a significant step for the manipulation of high-performance NIR photodetector of twodimensional covalent organic polymer-sensitized monolayer TMDCs.

Brønsted酸催化萘酚与丙炔醇的环化反应合成苯并色烯

苯并色烯广泛存在于天然产物、生物活性分子和有机功能材料中.报道了在温和条件下,以丙炔醇和β-萘酚为原料合成苯并色烯的策略,并以优秀的收率合成了一系列苯并色烯.该方案具有适用范围广、官能团兼容性好、条件温和等优点,且H2O是唯一副产物.此外,该方法操作简便,克级反应可以维持优秀收率,具有实际应用前景.