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Calculated Seebeck coefficient (a) and (b) electrical conductivity (c) and (d) and power factor (e) and (f) of GeC–TiSO, GeC–TiSeO, GeC–ZrSO and GeC–ZrSeO vdW heterostructures for 300 K and 800 K, respectively.

Highly effecient photo-Fenton catalysts of iron decorated boron nitride quantum dots were prepared.

Electronic band structure, type of Schottky contact and Schottky barrier height established at the interface of the CS–MX2 (M = Mo, W; X = S, Se, Te) and CS–MXY ((X ≠ Y) = S, Se, Te) MS vdWH.

Using density functional theory calculations, we have investigated the electronic band structure, optical and photocatalytic response of BSe, M2CO2 (M = Ti, Zr, Hf) monolayers and their corresponding BSe–M2CO2 (M = Ti, Zr, Hf) van der Waals heterostructures.

Low cost and highly efficient two dimensional materials as photocatalysts are gaining much attention to utilize solar energy for water splitting and produce hydrogen fuel as an alternative to deal with the energy crisis and reduce environmental hazards.

Using first-principles calculations, the geometry, electronic structure, optical and photocatalytic performance of blueP and XYO (X = Ti, Zr, Hf; Y = S, Se) monolayers and their corresponding van der Waal heterostructures in three possible stacking patterns, are investigated. BlueP and XYO (X = Ti, Zr, Hf; Y = S, Se) monolayers are indirect bandgap semiconductors. A tensile strain of 8(10)% leads to TiSeO(ZrSeO) monolayers transitioning to a direct bandgap of 1.30(1.61) eV. The calculated binding energy and AIMD simulation show that unstrained(strained) blueP and XYO (X = Ti, Zr, Hf; Y = S, Se) monolayers and their heterostructures are thermodynamically stable. Similar to the corresponding monolayers, blueP-XYO (X = Ti, Zr, Hf: Y = S, Se) vdW heterostructures in three possible stacking patterns are indirect bandgap semiconductors with staggered band alignment, except blueP-TiSeO vdW heterostructure, which signifies straddling band alignment. Absorption spectra show that optical transitions are dominated by excitons for blueP and XYO (X = Ti, Zr, Hf; Y = S, Se) monolayers and the corresponding vdW heterostructures. Both EVB and ECB in TiSO, ZrSO, ZrSeO and HfSO monolayers achieve energetically favorable positions, and therefore, are suitable for water splitting at pH = 0, while TiSeO and HfSeO monolayers showed good response for reduction and fail to oxidise water. All studied vdW heterostructures also show good response to any produced O2, while specific stacking reduces H+ to H2.

Constructing van der Waals (vdW) heterostructures is an exciting method for tuning the electronic and optical properties and the photocatalytic performances of two-dimensional materials. In this work, we investigated the electronic, optical and photocatalytic properties of a blue phosphorene–BAs (BlueP–BAs) vdW heterostructure using first-principles calculations. We found that the most energetically favorable stacking pattern of the BAs–BlueP vdW heterostructure possesses a direct band gap with type-I band alignment. The absorption spectrum of the BAs–BlueP vdW heterostructure showed that the lower energy transitions are dominated by excitons. Furthermore, the photocatalytic performance of the BAs–BlueP vdW heterostructure makes it suitable for water splitting at pH = 0. Our findings demonstrated that the BlueP–BAs heterostructure is a good candidate for optoelectronic and photocatalytic devices.

Designing van der Waals (vdW) heterostructures of two-dimensional materials is an efficient way to realize amazing properties as well as open up opportunities for applications in solar energy conversion, nanoelectronic and optoelectronic devices. The electronic structures and optical and photocatalytic properties of SiS, P and SiC van der Waals (vdW) heterostructures are investigated by (hybrid) first-principles calculations. Both binding energy and thermal stability spectra calculations confirm the stability of these heterostructures. Similar to the corresponding parent monolayers, SiS-P (SiS-SiC) vdW heterostructures are found to be indirect type-II bandgap semiconductors. Furthermore, absorption spectra are calculated to understand the optical behavior of these systems, where the lowest energy transitions lie in the visible region. The valence and conduction band edges straddle the standard redox potentials of SiS, P and SiC vdW heterostructures, making them promising candidates for water splitting in acidic solution.

Vertical heterostructures from two or more than two two-dimensional materials are recently considered as an effective tool for tuning the electronic properties of materials and for designing future high-performance nanodevices. Here, using first principles calculations, we propose a GeC/C2N van der Waals heterostructure and investigate its electronic and optical properties. We demonstrate that the intrinsic electronic properties of both GeC and C2N monolayers are quite preserved in GeC/C2N HTS owing to the weak forces. At the equilibrium configuration, GeC/C2N HTS forms the type-II band alignment with an indirect band gap of 0.42 eV, which can be considered to improve the effective separation of electrons and holes. Besides, GeC/C2N vdW-HTS exhibits strong absorption in both visible and near ultra-violet regions with an intensity of 105 cm−1. The electronic properties of GeC/C2N HTS can be tuned by applying an electric field and vertical strains. The semiconductor to metal transition can be achieved in GeC/C2N HTS in the case when the positive electric field of +0.3 V A−1 or the tensile vertical strain of −0.9 A is applied. These findings demonstrate that GeC/C2N HTS can be used to design future high-performance multifunctional devices.

The formation of van der Waals heterostructures (vdWHs) have recently emerged as promising structures to make a variety of novel nanoelectronic and optoelectronic devices. Here, in this work, we investigate the structural, electronic and optical features of ZnO/ZrSSe vdWHs for different stacking patterns of ZnO/SeZrS and ZnO/SZrSe by employing first-principles calculations. Binding energy and ab initio molecular dynamics calculations are also employed to confirm the structural and thermal stability of the ZnO/ZrSSe vdWHs for both models. We find that in both stacking models, the ZnO and ZrSSe layers are bonded via weak vdW forces, leading to easy exfoliation of the layers. More interestingly, both the ZnO/SeZrS and ZnO/SZrSe vdWHs posses type-II band alignment, making them promising candidates for the use of photovoltaic devices because the photogenerated electrons–holes are separated at the interface. The ZnO/ZrSSe vdWHs for both models possess high performance absorption in the visible and near-infrared regions, revealing their use for acquiring efficient photocatalysts. Moreover, the band gap values and band alignments of the ZnO/ZrSSe for both models can be adjusted by an electric field as well as vertical strains. There is a transformation from semiconductor to metal under a negative electric field and tensile vertical strain. These findings demonstrate that ZnO/ZrSSe vdWHs are a promising option for optoelectronic and nanoelectronic applications.

Modeling novel van der Waals (vdW) heterostructures is an emerging field to achieve materials with exciting properties for various devices. In this paper, we report a theoretical investigation of GaN–MX2 (M = Mo, W; X= S, Se) van der Waals heterostructures by hybrid density functional theory calculations. Our results predicted that GaN–MoS2, GaN–MoSe2, GaN–WS2 and GaN–WSe2 van der Waals heterostructures are energetically stable. Furthermore, we find that GaN–MoS2, GaN–MoSe2 and GaN–WSe2 are direct semiconductors, whereas GaN–WS2 is an indirect band gap semiconductor. Type-II band alignment is observed through PBE, PBE + SOC and HSE calculations in all heterostructures, except GaN–WSe2 having type-I. The photocatalytic behavior of these systems, based on Bader charge analysis, work function and valence and conduction band edge potentials, shows that these heterostructures are energetically favorable for water splitting.

Designing van der Waals (vdW) heterostructures of two-dimensional materials is an efficient way to realize amazing properties as well as opening opportunities for applications in solar energy conversion and nanoelectronic and optoelectronic devices. In this work, we investigate the electronic, optical, and photocatalytic properties of a boron phosphide–SiC (BP–SiC) vdW heterostructure using first-principles calculations. The relaxed configuration is obtained from the binding energies, inter-layer distance, and thermal stability. We show that the BP–SiC vdW heterostructure has a direct band gap with type-II band alignment, which separates the free electrons and holes at the interface. Furthermore, the calculated absorption spectra demonstrate that the optical properties of the BP–SiC heterostructure are enhanced compared with those of the constituent monolayers. The intensity of optical absorption can reach up to about 105 cm−1. The band edges of the BP–SiC heterostructure are located at energetically favourable positions, indicating that the BP–SiC heterostructure is able to split water under working conditions of pH = 0–3. Our theoretical results provide not only a fascinating insight into the essential properties of the BP–SiC vdW heterostructure, but also helpful information for the experimental design of new vdW heterostructures.

Favorable stacking patterns of two models with alternative orders of chalcogen atoms in SiC-MSSe (M = Mo, W) vdW heterostructures are investigated using density functional theory calculations. Both model-I and model-II of the SiC-MSSe (M = Mo, W) vdW heterostructures show type-II band alignment, while the spin orbit coupling effect causes considerable Rashba spin splitting. Furthermore, the plane-average electrostatic potential is also calculated to investigate the potential drops across the heterostructure and work function. The imaginary part of the dielectric function reveals that the first optical transition is dominated by excitons with high absorption in the visible region for both heterostructures. Appropriate band alignments with standard water redox potentials enable the capability of these heterostructures to dissociate water into H+/H2 and O2/H2O.

Correction for ‘First principles study of electronic and optical properties and photocatalytic performance of GaN–SiS van der Waals heterostructure’ by S. S. Sabir et al., RSC Adv., 2021, 11, 32996–33003, https://doi.org/10.1039/D1RA06011B.

Using density functional (DFT) theory calculations, we have investigated the electronic band structure, optical and photocatalytic response of BSe, M

The vertical stacking of two-dimensional materials via van der Waals (vdW) interaction is a promising technique for tailoring the physical properties and fabricating potential devices to be applied in the emerging fields of materials science and nanotechnology. The structural, electronic and optical properties and photocatalytic performance of a GaN–SiS vdW heterostructure were explored using first principles calculations. The most stable stacking configuration found energetically stable, possesses a direct staggered band gap, which is crucial for separating photogenerated charged carriers in different constituents and is efficacious for solar cells. Further, the charge transfer occurred from the SiS to GaN layer, indicating that SiS exhibits p-type doping in the GaN–SiS heterobilayer. Interestingly, a systematic red-shift was observed in the optical absorption spectra of the understudy heterobilayer system. Moreover, the conduction band edge and valence band edge of the monolayers and corresponding heterostructure were located above and below the standard redox potentials for photocatalytic water splitting, making these systems promising for water dissociation for hydrogen fuel production. The results provide a route to design the GaN–SiS vdW heterostructure for the practical realization of next-generation light detection and energy harvesting devices.

Outbreaks of cobweb disease are becoming increasingly prevalent globally, severely affecting the quality and yield of Agaricus bisporus. However, cobweb disease-resistant strains are rare, and little is known regarding the biocontrol management of the disease. Here, we isolated a pathogen from a severe outbreak of cobweb disease on A. bisporus in China and identified it as Cladobotryum mycophilum based on morphological characteristics, rDNA sequences, and pathogenicity tests. We then tested 30 A. bisporus strains for cobweb disease resistance by inoculating with C. mycophilum and evaluated the activity of different botanicals. We found that two wild strains of A. bisporus originating from the Tibetan Plateau in China were resistant to cobweb disease, and four commercial strains were susceptible. Yield comparisons of the inoculated and uninoculated strains of A. bisporus with C. mycophilum revealed yield losses of 6–38%. We found that seven botanicals could inhibit C. mycophilum growth in vitro, particularly Syzygium aromaticum, which exhibited the maximum inhibition (99.48%) and could thus be used for the further biocontrol of cobweb disease. Finally, we identified the bioactive chemical constituents present in S. aromaticum that could potentially be used as a treatment for C. mycophilum infection using Fourier transform infrared (FTIR) spectroscopy. These findings provide new germplasm resources for enhancing A. bisporus breeding and for the identification of botanicals for the biocontrol of cobweb disease.

Size-tunability of the electronic and optical properties of semiconductor quantum dots and nanoclusters is due to the quantum size effect, which causes variations in the electronic excitations as the particle boundaries are changed. Recently, CdSe and CdTe quantum dots have been used in energy harvesting devices. Despite these promising practical applications, a complete understanding of the electronic transitions associated with the surfaces of the nanoparticles is currently lacking and is difficult to achieve experimentally. Computational methods could provide valuable insights and allow us to understand the electronic and optical properties of quantum dots and nanoclusters. Hollow cage and endohedral or core–shell cage structures for CdnTen clusters have been reported before. We have performed systematic density functional theory (DFT) studies on the structure and electronic properties of the CdnTen (n = 1–17) clusters. As the number of atoms increases in the CdnTen clusters, the predicted geometries change from simple planar structures to more complicated 3D-structures. Two classes of the most stable structures were elucidated for clusters with n = 10–17: (i) hollow cage structures with an empty center; and (ii) endohedral or core–shell cage structures with one or more atoms inside the cage. Noticeably higher highest occupied molecular orbital (HOMO)-lowest unoccupied molecular orbital (LUMO) gaps were observed for the hollow cage isomers as compared to the core–shell structures. The highest occupied molecular orbitals of all of the clusters studied were shown to be localized on the surface of the cage for the hollow cage structures, while in the case of the core–shell structures, the HOMO electron densities were found to be distributed both on surface and the interior of the structures. Most of the small size clusters CdnTen (n = 2–9) showed minimal values for the dipole moments (close to zero) owing to the highly ordered and symmetric configurations of these structures. For isomers of the larger clusters (n = 10–17), it was observed that the core–shell structures have higher values for the dipole moments than the hollow cage species because of the highly symmetric structures of the hollow cages. Core–shell cage structures exhibited lower polarizability than the respective hollow cage structures.

In this work, we perform first-principles calculations to examine the electronic, optical and photocatalytic properties of the BX–ZnO (X = As, P) heterostructures. The interlayer distance and binding energy of the most energetically favorable stacking configuration are 3.31 A and −0.30 eV for the BAs–ZnO heterostructure and 3.30 A and −0.25 eV for the BP–ZnO heterostructure. All the stacking patterns of the BX–ZnO heterostructures are proved to have thermal stability by performing AIMD simulations. The BAs–ZnO and BP–ZnO heterostructures are semiconductors with direct band gaps of 1.43 eV and 2.35 eV, respectively, and they exhibit type-I band alignment, which make them suitable for light emission applications with the ultra-fast recombination between electrons and holes. Both the BAs–ZnO and BP–ZnO heterostructures can exhibit a wider optical absorption range for visible-light owing to their reduced band gaps compared with the isolated BAs, BP and ZnO monolayers. The band alignment of both the BAs–ZnO and BP–ZnO heterostructures can straddle the water redox potential and they would have better performances owing to the direct band gap and the reduced band gap. All these findings demonstrate that the BX–ZnO heterostructures can be considered as potential photocatalysts for water splitting.

In this work, we systematically studied the electronic structure and optical characteristics of van der Waals (vdW) heterostructure composed of a single layer of GaN and GeC using first principles calculations. The GaN–GeC vdW heterostructure exhibits indirect band gap semiconductor properties and possesses type-II energy band arrangement, which will help the separation of photogenerated carriers and extend their lifetime. In addition, the band edge positions of the GaN–GeC heterostructure meet both the requirements of water oxidation and reduction energy, indicating that the photocatalysts have the potential for water decomposition. The GaN–GeC heterostructure shows obvious absorption peaks in the visible region, leading to the efficient use of solar energy. Tensile and compressive strains of up to 10% are also proposed. Tensile strain leads to an increase in the blue shift of optical absorption, whereas a red shift is observed in the case of the compressive strain. These fascinating characteristics make the GaN–GeC vdW heterostructure a highly effective photocatalyst for water splitting.

Modeling novel van der Waals (vdW) heterostructures is an emerging field to achieve materials with exciting properties for various devices. In this paper, we report a theoretical investigation of GaN-MX

Vertical heterostructures from two or more than two two-dimensional materials are recently considered as an effective tool for tuning the electronic properties of materials and for designing future high-performance nanodevices. Here, using first principles calculations, we propose a GeC/C

Outbreaks of cobweb disease are becoming increasingly prevalent globally, severely affecting the quality and yield of

Mesoporous nickel cobaltite (NiCo2O4) nanosheets are synthesized using a cost effective, ultra fast and environmentally friendly microwave assisted heating method followed by a post-calcination process of the as-prepared precursors. XRD, XPS, BET, SEM, TEM and HRTEM methods are used to characterize the nanosheets. The as-prepared nanosheets with a thickness of around 2 nm possess many interparticle mesopores. The nanosheets have a mesoporous structure, high specific surface area (111.15 m2 g−1), large pore volume (0.3033 cm3 g−1) and narrow pore size distribution (2.25–10 nm). A flexible supercapacitor working electrode of the mesoporous NiCo2O4 nanosheets is prepared on carbon cloth. Cyclic voltammetry, chronopotentiometry and impedance spectroscopy measurements are used to investigate the electrochemical performance of the as-prepared mesoporous NiCo2O4 nanosheet/carbon cloth electrode. The mesoporous NiCo2O4 nanosheets exhibit specific capacitances of 292.5 and 200 F g−1 in 2 M KOH aqueous electrolyte at current densities of 1 and 8 A g−1 respectively. The cyclic performance indicates excellent capacitance retention of 94.5% after 2000 cycles at a current density of 3 A g−1. The excellent cyclic stability can be attributed to the mesoporous nature, high specific surface area, large pore volume and narrow pore distribution of the nanosheets. The synthesized mesoporous NiCo2O4 nanosheets using a microwave method are proved to be excellent electrode material for advanced flexible supercapacitors.

A novel Z-scheme WO3/CdWO4 photocatalyst has been fabricated with sheet-like tungsten trioxide (WO3) hybridized by rod-like cadmium tungstate (CdWO4) via a hydrothermal and chemisorption method. The as-synthesized WO3/CdWO4 photocatalyst exhibited enhanced photocatalytic efficiency for the degradation of different organic dyes under visible light irradiation. It was found that the photocatalytic performance of the composite WO3/CdWO4 was much higher than that of either WO3 or CdWO4 for the degradation of each organic dye. The highest activity of the composite was recorded for the degradation of MB which was about 7 times greater than pure CdWO4 and 2.3 times that of pure WO3. The enhanced performance of the photocatalyst was mainly attributed to the increased surface area and introduction of WO3 into the composite sample, which can induce higher adsorption activity for organic dyes and increased electron–hole separation at the interface between two semiconductors by establishing an inner electric field.

First-principles density functional theory (DFT) calculations were carried out to investigate the structural and electronic properties of beryllium (Be) doped and Be and boron (B) co-doped graphene systems. We observed that not only the concentration of impurity atoms is important to tune the band-gap to some desired level, but also the specific substitution sites play a key role. In our system, which consists of 32 atoms, a maximum of 4Be and, in the co-doped state, 2Be and 3B atom substitutions are investigated. Both dopants are electron deficient relative to C atoms and cause the Fermi level to shift downward (p-type doping). A maximum band gap of 1.44 eV can be achieved on incorporation of 4Be atoms. The introduction of Be is more sensitive in terms of geometry and stability than B. However, in opening the energy gap, Be is more effective than B and N (nitrogen). Our results offer the possibility to modify the band-gap of graphene sufficiently for utilization in diverse electronic device applications.