In this article, the optical, magnetic, and electronic of pristine and transition metals (TM) adsorbed Pd 2 Se 3 were systematically researched by density functional theory. The results reveal that the most stable position of Pd 2 Se 3 monolayer adsorbed by various TM is different. The band structures of Au-, Cu- and Sc–Pd 2 Se 3 structures demonstrate nonmagnetic metal behaviour, while the Co- and Cr–Pd 2 Se 3 structures display magnetic metal properties. Meanwhile, the Ni- and Pt–Pd 2 Se 3 systems show nonmagnetic semiconductor character, and Fe- and Mn–Pd 2 Se 3 systems exhibit magnetic semiconductor features. Moreover, the work function of Au-, Cu-, Co-, Mn- and Fe–Pd 2 Se 3 structures is lower than Pd 2 Se 3 monolayer, which demonstrates that these structures have good electron emission characteristics. Interestingly, after the adsorption of TM atom, the light absorption of Pd 2 Se 3 system in various regions is boosted to varying degrees, indicating that the introduction of TM atom can improve the light absorption of Pd 2 Se 3 system in ultraviolet, visible and infrared regions. Therefore, it demonstrates that TM-Pd 2 Se 3 systems can be used to fabricate spintronic, photocatalysts and optoelectronic devices. • The most stable positions of Pd 2 Se 3 adsorbed by various TM are different. • The Ni- and Pt–Pd 2 Se 3 systems show nonmagnetic semiconductor character, and Fe- and Mn–Pd 2 Se 3 systems exhibit magnetic semiconductor. • The work function of Au-, Cu-, Co-, Mn- and Fe–Pd 2 Se 3 structures is lower than that of Pd 2 Se 3 . • The introduction of TM atom can improve the light absorption of Pd 2 Se 3 system in ultraviolet, visible and infrared regions. 

Optoelectronic and magnetic properties of transition metals adsorbed Pd2Se3 monolayer

The graphitic C 3 N 4 (g-C 3 N 4 ) is a new non-metallic semiconductor material , which has the advantages of high thermal, sensitive visible light response and stability. It has great application potential in the fields of hydrogen production by water decomposition, organic matter degradation, gas sensing and carbon dioxide reduction. In this article, two-dimensional (2D) g-C 3 N 4 nanosheets and their nanocomposites were prepared, and the photocatalytic degradation of organic compounds was investigated. Field emission scanning electron microscope (FESEM) test demonstrates that the thickness of g-C 3 N 4 nanosheets stripped from g-C 3 N 4 material is uniform and thin. The X-ray diffraction demonstrates that the g-C 3 N 4 nanosheet is a 3- s -triazine ring crystal structure. Furthermore, g-C 3 N 4 /MoS 2 nanocomposites were fabricated by impregnation calcination method. FESEM showed that the g-C 3 N 4 /MoS 2 nanocomposites exhibited nanosheets with uniform thickness. Transmission electron microscopy and X-ray photoelectron spectroscopy illustrated that the composites had both g-C 3 N 4 and MoS 2 components. Moreover, the experiment of photocatalytic degradation of Rhodamine B exhibited that after 90 min illumination, and the degradation efficiency of g-C 3 N 4 , g-C 3 N 4 nanosheets, MoS 2 and g-C 3 N 4 /MoS 2 nanocomposites were 80.2%, 91%, 91.5% and 99.4%, respectively. The degradation rate of g-C 3 N 4 /MoS 2 nanocomposites was 2.1 times that of g-C 3 N 4 nanosheets. Therefore, the successful combination of MoS 2 and g-C 3 N 4 has significantly improved the photocatalytic properties of g-C 3 N 4 nanosheets. 

Fabrication of a g-C3N4/MoS2 photocatalyst for enhanced RhB degradation

Adsorption of metal atoms on MoSi2N4 monolayer: A first principles study

The configurations of nine different non-metals doped silicon carbide (NM-SiC) were structured by using the density functional theory (DFT). The magnetic, electronic, and optical properties of each NM-SiC are investigated at the most stable structure with the maximum binding energy. Although the O-, Si-, and S-SiC systems are still non-magnetic semiconductors, the N- and P-SiC systems have the properties of the magnetic semiconductors. The H-, F-, and Cl-SiC systems exhibit the half-metal behaviors, while the B-SiC system converts to magnetic metal. The redistribution of charges occurs between non-metals atoms and adjacent C atoms. For the same doping position, the more charges are transferred, the greater the binding energy of the NM-SiC system. The work function of the NM-SiC systems is also adjusted by the doping of NM atoms, and achieves the minimum 3.70 eV in the P-SiC, just 77.1% of the original SiC. The absorption spectrum of the NM-SiC systems occurs red-shift in the ultraviolet light region, accompanying the decrease of absorption coefficient. These adjustable magnetic, electronic, and optical performances of NM-SiC expand the application fields of two-dimensional (2D) SiC, especially in designing field emission and spintronics devices.

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Electronic, Magnetic, and Optical Performances of Non-Metals Doped Silicon Carbide

Toxic gas molecular adsorbed on intrinsic and defective WS2: gas sensing and detection

MoSi2N4 is a recently developed 2D material that exhibits remarkable thermal, mechanical, electronic, and optical properties. We used first principles calculations to study the structural and electronic properties of organic molecule doped MoSi 2N4 monolayers. Effective p-doping was achieved by molecular doping with tetracyanoquinodimethane and tetracyanoethylene, while n-doping was achieved by molecular doping with tetrathiafulvalene. The doping gap of tetrathiafulvalene-doped MoSi2N4 was successfully modulated by the application of an external electric field, which resulted in effective n-doping. Furthermore, molecular doping injects additional carriers into the host, which is beneficial for enhancing the performance of MoSi2N4 in nanoelectronic devices. Our results demonstrate the importance of molecular doping in tuning the electronic properties of MoSi 2N4 and broadening its applications.

Zhen Cui

Papers

Tuning the electronic properties of MoSi2N4 by molecular doping: A first principles investigation