Search

Adjusting the electronic and magnetic properties of materials by strain engineering is an effective strategy to improve the performance of electronic and spin electronic devices. In this paper, we study the electronic and magnetic properties of Cr 2 C and Cr 2 CX 2 (X = F, O,OH) under mechanical strain based on density functional theory. In the strain-free state, Cr 2 C and Cr 2 CO 2 are in the ferromagnetic (FM) metallic ground states, while Cr 2 CF 2 and Cr 2 C(OH) 2 are in the antiferromagnetic (AFM) semiconducting states. Applying tensile strain can enhance the magnetic moments of the Cr atoms of all the Cr 2 C and Cr 2 CX 2 (X = F, O, OH) systems. The electronic structure can also be affected with the increase of strain, e.g., resulting in narrowing of the band gap of the AFM semiconducting systems (Cr 2 CF 2 and Cr 2 C(OH) 2) and enhancing the spin-splitting of the FM metallic systems (Cr 2 C and Cr 2 CO 2). The results indicate a possible broadened applicability of strained Cr 2 C-based MXenes in future spintronics. • In the strain-free state, Cr 2 C and Cr 2 CO 2 are in the ferromagnetic (FM) metallic ground states, while Cr 2 CF 2 and Cr 2 C(OH) 2 are in the antiferromagnetic (AFM) semiconducting states. • Applying tensile strain can enhance the magnetic moments of the Cr atoms of all the Cr 2 C and Cr 2 CX 2 (X = F, O, OH) systems. • Applying tensile strain can change the electronic properties and magnetic properties of the system. [ABSTRACT FROM AUTHOR]

The alternating diketopyrrolopyrrole (DPP)-Quinoxaline (Qx) based conjugated polymers are synthesized and investigated as electron donors for polymer solar cells (PSCs). Through the substitution of phenyl in Qx unit at para ( p ) and meta ( m ) positions with methoxy group, the resultant DPP- p MQx and DPP- m MQx polymers possess narrow optical band gap (1.32 and 1.26 eV) with relatively low-lying highest occupied molecular orbitals. The obtained photovoltaic devices indicate that the combination of DPP with weak acceptor Qx is helpful to develop narrow bandgap polymers with near-infrared photo response and low energy loss (0.58 eV for DPP- m MQx) in PSC devices. [ABSTRACT FROM AUTHOR]

Antimony sulfide (Sb 2 S 3) is widely used in photocatalysts and photovoltaic cells because of its abundant reserves, low toxicity, environmental friendliness, narrow band gap, and high light absorption capacity. Sb 2 S 3 shows a quasi-one-dimensional structure composed of [Sb 4 S 6 ] n nanoribbons, a lot of reported studies are focused on preparing Sb 2 S 3 with [hk1] oriented dominant growth to improve the photogenerated carrier transport capacity of Sb 2 S 3. However, there is relatively few research on the preparation of [hk1] oriented rod-like Sb 2 S 3 by vapor transport deposition (VTD) method. In this work, the VTD method was used to prepare Sb 2 S 3 with [hk1] oriented growth on the FTO substrate, and then composite with the ternary solid solution Cd x Zn 1−x S. Finally, a novel Sb 2 S 3 /Cd 0.6 Zn 0.4 S S-scheme heterojunction with rod-like core-shell structure was successfully constructed, which could effectively improve the photoelectrochemical properties. Because the solid solution component x is adjustable, that is, Cd x Zn 1−x S has continuously adjustable band gap width and energy level position, the Sb 2 S 3 /Cd x Zn 1−x S heterojunction type can be regulated from Type-II to S-scheme. Photoelectrochemical (PEC) tests indicated that the composite photoanode Sb 2 S 3 /Cd 0.6 Zn 0.4 S achieved a higher photocurrent density (2.54 mA·cm−2, 1.23 V vs. RHE), which is about 4.31 times that of pure Sb 2 S 3 nanorod photoanode (0.59 mA·cm−2, 1.23 V vs. RHE). • Rod-like Sb 2 S 3 with [hk1] orientation is deposited on FTO substrate by VTD method. • The Sb 2 S 3 /Cd x Zn 1−x S heterojunction type can be regulated from Type-Ⅱ to S-scheme. • The S-scheme heterojunction could effectively promote PEC water splitting. • The photoelectrode exhibits considerable photocurrent 2.54 mA·cm−2 at 1.23 V RHE. [ABSTRACT FROM AUTHOR]

Abstract: Dissolved organic matter (DOM) plays a critical role in the transport of carbon nano-particles (e.g. C60) in the aquatic environment. However, the mechanism for C60-DOM interactions and its environmental implications needs further investigations. In this study, the interaction of C60 with relevant reference compounds of DOM (DOMR) is computationally simulated by molecular mechanics and density functional theory (DFT). All the C60-DOMR complexes are firstly optimized by classical annealing, and then DFT using the Dmol3 code. The adsorption energies of C60 on DOMR were computed. The computed electrostatic potential indicates that DOMR are electron acceptors in the C60-DOMR complexes, and the thermodynamic calculations indicate that electrostatic interaction is the dominant driving force for the C60-gallic acid complexation process in water. The presence of DOMR increases the apparent water solubility of C60. It is also observed that the C60 apparent water solubility decrease with the increase of the energy gaps of frontier molecular orbitals (E LUMO–E HOMO) for each C60-DOMR complex. These findings indicate that computational simulation is an important tool for predicting the behavior and fate of carbon nano-particles in the aquatic environment. [Copyright &y& Elsevier]

[Display omitted] • Low-cost Sb 2 S 3-x Se x photocathode using Se powder as Se source was fabricated. • The effect of NiFe-LDH hole blocking and Ni2+ HER activity enhanced performance. • Sb 2 S 3-x Se x /NiFe-LDH photocathode exhibited −1.21 mA cm−2 at 0 V RHE. The alloyed Sb 2 S 3-x Se x has attracted widespread attention as a promising light absorbing material in recent years because it has the advantages of both Sb 2 S 3 and Sb 2 Se 3 , such as adjustable band gap in the range of 1.1–1.8 eV and good stability. However, expensive selenourea enormously increases its manufacturing cost. In this paper, using Se powder as Se source, high-quality and low-cost Sb 2 S 3-x Se x film photoelectrode is successfully prepared by one-step hydrothermal method, and applied to photoelectrochemical (PEC) water splitting. Furthermore, with the help of NiFe-layered double hydroxide (LDH) modification, an increase in photocurrent density from −0.22 mA cm−2 to −1.21 mA cm−2 at 0 V RHE is achieved, and the onset potential is positively shifted by 120 mV. NiFe-LDH significantly improve hydrogen evolution reaction (HER) performance. The relevant characterization can confirm that this is mainly due to the blocking effect of NiFe-LDH on photogenerated holes, promoting effect of Ni2+ on the kinetics of hydrogen evolution reactions, and the strengthening of bulk charge separation efficiency. Undoubtedly, this work opens up a simple and effective way for the development of low-cost, high-efficiency antimony chalcogenides photoelectrodes, and provides new ideas for its excellent application in the field of PEC water splitting. [ABSTRACT FROM AUTHOR]