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We incorporate Se into the 3D halide perovskite framework using the zwitterionic ligand: SeCYS (+NH3(CH2)2Se-), which occupies both the X- and A+ sites in the prototypical ABX3 perovskite. The new organoselenide-halide perovskites: (SeCYS)PbX2 (X=Cl, Br) expand upon the recently discovered organosulfide-halide perovskites. Single-crystal X-ray diffraction and pair distribution function analysis reveal the average structures of the organoselenide-halide perovskites, whereas the local lead coordination environments and their distributions were probed through solid-state 77Se and 207Pb NMR, complemented by theoretical simulations. Density functional theory calculations illustrate that the band structures of (SeCYS)PbX2 largely resemble those of their S analogs, with similar band dispersion patterns, yet with a considerable band gap decrease. Optical absorbance measurements indeed show band gaps of 2.07 and 1.86 eV for (SeCYS)PbX2 with X=Cl and Br, respectively. We further demonstrate routes to alloying the halides (Cl, Br) and chalcogenides (S, Se) continuously tuning the band gap from 1.86 to 2.31 eV-straddling the ideal range for tandem solar cells or visible-light photocatalysis. The comprehensive description of the average and local structures, and how they can fine-tune the band gap and potential trap states, respectively, establishes the foundation for understanding this new perovskite family, which combines solid-state and organo-main-group chemistry.

Coupling Weyl quasiparticles and charge density waves (CDWs) can lead to fascinating band renormalization and many-body effects beyond band folding and Peierls gaps. For the quasi-one-dimensional chiral compound (TaSe4)2I with an incommensurate CDW transition at TC = 263 K, photoemission mappings thus far are intriguing due to suppressed emission near the Fermi level. Models for this unconventional behavior include axion insulator phases, correlation pseudogaps, polaron subbands, bipolaron bound states, etc. Our photoemission measurements show sharp quasiparticle bands crossing the Fermi level at T > TC, but for T < TC, these bands retain their dispersions with no Peierls or axion gaps at the Weyl points. Instead, occupied band edges recede from the Fermi level, opening a spectral gap. Our results confirm localization of quasiparticles (holes created by photoemission) is the key physics, which suppresses spectral weights over an energy window governed by incommensurate modulation and inherent phase defects of CDW.

Aiming at an efficient method to determine the transport properties of a physical system, an effective and accurate band‐counting algorithm is presented to extract the transmission spectrum of a low‐dimensional system, directly from the band structure. This approach is more efficient than Hamiltonian‐dependent formalisms such as the standard Green's function (GF) or the transfer matrix methods. The only constraint of the approach is that the bands should not be mixed, i.e., for each band in the k‐path, there should be a set of eigenvalues. The efficiency of the approach is comparable to that of Green's function method, and it is applicable to any computational approach whose output is a band structure, whether for particles or quasiparticles such as electrons and phonons. Since the transport coefficient is calculated separately for each band, the occurrence of eigenvalues at the same k‐point can be captured by the algorithm. The proposed algorithm will be useful for studying transmission coefficient‐dependent quantities, such as thermoelectric‐related quantities, and also the electric current within the Landauer–Büttiker formalism. [ABSTRACT FROM AUTHOR]

The Berry phase is a fundamental concept in quantum mechanics with profound implications for understanding topological properties of quantum systems. This tutorial provides a comprehensive introduction to the Berry phase, beginning with the essential mathematical framework required to grasp its significance. We explore the intrinsic link between the emergence of a non-trivial Berry phase and the presence of topological characteristics in quantum systems, showing the connection between the Berry phase and the band structure as well as the phase's gauge-invariant nature during cyclic evolutions. The tutorial delves into various topological effects arising from the Berry phase, such as the quantum, anomalous, and spin Hall effects, which exemplify how these quantum phases manifest in observable phenomena. We then extend our discussion to cover the transport properties of topological insulators, elucidating their unique behaviour rooted in the Berry phase physics. This tutorial aims at equipping its readers with a robust understanding of the basic theory underlying the Berry phase and of its pivotal role in the realm of topological quantum phenomena. [ABSTRACT FROM AUTHOR]

The positive and negative parity rotational band structures of odd–odd Nb isotopes with atomic masses 90, 92 and 94 are investigated using the theoretical framework of the projected shell model. These odd–odd nuclei are found to be ideal for investigating the significant structural changes occurring in the region situated far from the valley of stability. This is the first time that such comprehensive theoretical data for both positive and negative parities together for the odd–odd 90−94Nb isotopes have been disclosed. The g-factor and electromagnetic transition probabilities are among the various nuclear structure quantities that are examined for the first time. Using a broad configuration space for both protons and neutrons, the computed data have been anticipated up to high spin values. [ABSTRACT FROM AUTHOR]

Electronic effects of organic functional groups play a fundamental role in determining the rate and/or direction of organic chemical reactions. The implementation of this concept in selective organic catalysis is achieved by tuning the electronic effects of organic functional groups to alter the corresponding reactivity. However, this approach has hardly been applied to modulate the band structure of inorganic materials. Here, we show that modulating the electronic band structure of two‐dimensional black phosphorus (BP) is possible via the electronic effects of organic functional groups covalently modified on its surface. Organic functional group can either donate or withdraw charge density from BP surface, which will alter the bonding/anti‐binding orbitals occupancy and thus shift the band‐edge positions of functionalized BP downward/upward. Therefore, the valence‐band maxima and the conduction‐band minima of functionalized BP can be continuously tuned by changing the binding group with different Hammett parameters. Finally, unexpectedly high hydrogen evolution reaction rates under visible light are achieved using functionalized BP heterojunctions as photocatalysts. This work underscores the significant role of electronic effects in chemically controlling BP's band structure, offering greater flexibility and affordability beyond physical method limits. [ABSTRACT FROM AUTHOR]

In this study, cerium dioxide (CeO 2) materials doped with one (Gd3+, GDC), two (Gd3+ and Na+, GNDC), and three (Gd3+, Na+, and Eu3+, EGNDC) components were, respectively, prepared, and their high-temperature infrared emissivity was investigated through experimental measurements and theoretical calculations. The experimental results show that GDC exhibits the highest oxygen vacancy concentration, highest conductivity, and narrowest band gap; furthermore, it exhibits an ultralow infrared emissivity (0.202 at 600 °C). The band structure calculations reveal that the Fermi level of GDC shows the highest total density of states, and electrons are more likely to enter the conduction band, which increases the conductivity and thus reduces the infrared emissivity. Furthermore, the infrared reflectance decreases gradually with increasing number of doping components, and the highest infrared reflectance and lowest infrared emissivity for GDC are obtained at 3–5 μm. These findings are consistent with the experimental results. [ABSTRACT FROM AUTHOR]

In this research, and photoelectric properties of two possible allotropes β12-borophene and δ6-borophene have been investigated using first-principles calculations for 1–4 borophene layers. The band structures, charge density, partial density of states, electrostatic potential and absorption spectra are calculated for multilayer borophene. The obtained results indicate that all layers exhibit anisotropic metallic behavior due to the interlayer charge transfer in β12-borophene and δ6-borophene. Furthermore, band splitting was increased with layer number, which was more pronounced in β12-borophene. This finding was verified by the partial density of states. Moreover, the anisotropic structure of β12-borophene and δ6-borophene is evident in the calculated absorbance, which, while relatively low, distinctly exhibits a dependence on the number of layers. Meanwhile, multilayer borophene was almost transparent in visible region with weak absorption, which reflected its anisotropic structure. Density functional theory results suggested that multilayer borophene provided a critical basis for future research on photonic technology. These findings highlighted the substantial potential of multilayer borophene for photonic technology. [ABSTRACT FROM AUTHOR]

In this contribution, we address quantum transport in long periodic arrays whose basic cells, localized potentials U (x) , display certain particular features. We investigate under which conditions these "local" special characteristics can influence the tunneling behavior through the full structure. As the building blocks, we consider two types of U (x) s: combinations of either Pöschl–Teller, U 0 / cosh 2 [ α x ] , potentials (for which the reflection and transmission coefficients are known analytically) or Gaussian-shaped potentials. For the latter, we employ an improved potential slicing procedure using basic barriers, like rectangular, triangular and trapezoidal, to approximate U (x) and thus obtain its scattering amplitudes. By means of a recently derived method, we discuss scattering along lattices composed of a number, N, of these U (x) s. We find that near-resonance energies of an isolated U (x) do impact the corresponding energy bands in the limit of very large Ns, but only when the cell is spatially asymmetric. Then, there is a very narrow opening (defect or rip) in the system conduction quasi-band, corresponding to the energy of the U (x) quasi-state. Also, for specific U 0 's of a single Pöschl–Teller well, one has 100% transmission for any incident E > 0 . For the U (x) parameters rather close to such a condition, the associated array leads to a kind of "reflection comb" for large Ns; | T N (k) | 2 is not close to one only at very specific values of k, when | T N | 2 ≈ 0 . Finally, the examples here—illustrating how the anomalous transport comportment in finite but long lattices can be inherited from certain singular aspects of the U (x) s—are briefly discussed in the context of known effects in the literature, notably for lattices with asymmetric cells. [ABSTRACT FROM AUTHOR]

Quaternary chalcogenide compositions have gained much attention because of their promising potential for various optoelectronic applications. The band structure, density of states, and optical properties of CuZn2InS4 and CuZn2GaS4 for kesterite and stannite structures are studied with the full-potential augmented plane wave method as implemented in the Wien2k code. The total energy in equilibrium is calculated for different possible crystal structures. The phase stability and transitions with p–d orbitals are also analyzed. Moreover, the absorption coefficient, dielectric function, and refractive index of these materials are explored within a broad range of energy. We compare the calculated band gap values with available experimental results. [ABSTRACT FROM AUTHOR]

The phosphors for pc-LEDs have high thermal stability requirements due to the high operating temperature of LEDs. In addition, there are many phosphors based on SrNb 2 O 6 , but no one has studied Sm3+ or Tb3+ as the luminescent center of SrNb 2 O 6 host. Therefore, two new phosphors based on SrNb 2 O 6 host are proposed in this work. One is an orange phosphor with negative thermal quenching phenomenon using Sm3+ as the luminescent center, and the other is a green phosphor with Tb3+ as the luminescent center. In this work, a series of SrNb 2 O 6 :Sm3+ and SrNb 2 O 6 :Tb3+ phosphors were prepared by the solid-state reaction method. The structure, morphology, chemical composition, absorption properties and luminescence properties of Sm3+ and Tb3+ doped SrNb 2 O 6 samples were studied. Under 405 nm excitation, the SrNb 2 O 6 :Sm3+ samples exhibit the 4f-4f transition of Sm3+ with the strongest emission intensity at 607 nm, the emission intensity of SrNb 2 O 6 :0.03Sm3+ phosphor at 150 °C remains at 100.56% of its room temperature value and the chromaticity coordinates are located in the orange region, with a color purity of 88.19%. Under 307 nm excitation, the SrNb 2 O 6 :Tb3+ samples exhibit the 4f-4f transition of Tb3+ with the strongest emission intensity at 544 nm, the emission intensity of SrNb 2 O 6 :0.09Tb3+ phosphor at 150 °C remains at 7.68% of its room temperature value and the chromaticity coordinates are located in the green region with a color purity of 74.29%. Additionally, Na+ is introduced as a charge compensator in the Sm3+ or Tb3+ doped phosphors, which enhances their luminescence intensity. These results indicate that the two phosphors synthesized in this work have the prospect of application in the field of solid-state lighting. [ABSTRACT FROM AUTHOR]

Based on density functional theory (DFT), a two-dimensional(2D) metal-organic framework (MOF) based on Co and Cu atoms were presented. Based on the phonon dispersion calculations, no imaginary mode is found in the phonon branches, which verifies that the crystal structures of MOF could be stable. Based on the calculation of electronic band structure, it is found that the Cu-based MOF is a metallic system by applying external electric field. While the Co-based MOF undergoes a transition from metal to semiconductor under external electric field. When the external electric field intensity reaches up to 0. 5 eV/Å, the band gap of Co-based MOF is around 0. 1 eV, while this does not happen in the Cu-based MOF. Furthermore, the N2 adsorption and the nitrogen reduction reaction (NRR) were investigated for the Co-based MOF, which shows that the NRR for the Co-based MOF exhibits good performance, and the electric field could enhance this effect of NRR. The free energy of NRR under external electric field of 0. 5 eV/Å is 0. 51 eV lower than that without electric field. Therefore, our study would prospectively guide the experimental researchers on the design of NRR. [ABSTRACT FROM AUTHOR]

Pb‐free perovskites are novel compounds that are currently being studied, essentially for their photovoltaic applications. In this article, the hybrid organic–inorganic perovskite for photovoltaic applications is studied. In fact, the structural and electronic properties of the perovskite FABI3 (B = Sn, Ge, or Pb and FA = formamidinium: CH(NH2)2) applying the density functional theory method executed in the Quantum Espresso framework are studied and discussed. The band structures of these perovskites have been presented; it is shown that these perovskites have a semiconductor nature, with a bandgap value of 1.36 eV for FASnI3, 1.72 eV for FAGeI3, and 1.61 eV for FAPbI3. Also, the density of states and partial density of states have been presented and discussed for each of these materials. Indeed, the structural properties of these perovskites are investigated and demonstrated that the optimized value of the lattice parameter is 6.35 Å for the FASnI3, while for the FAGeI3, this value is 6.3 Å and 6.5 Å for FAPbI3. Moreover, the impact of the lattice parameter on the bandgap value of FABI3 (B = Sn, Ge, or Pb) has been investigated, and it has been demonstrated that as the lattice parameter increases, the bandgap increases. The results of this work can be utilized as a guideline for the development of new efficient, lead‐free perovskite devices, including tandem solar cells. [ABSTRACT FROM AUTHOR]

Understanding the properties of lithium vacancy, LiCV, defects in diamond is crucial for optimizing diamond-based semiconductor performance and unlocking its full potential in advanced electronic applications. In this study, we present a comprehensive theoretical investigation of the neutral LiCV defect, resulting from the interaction between a lithium substitutional and a vacancy, in diamond. Employing periodic supercell calculations, we utilize global (B3LYP and PBE0) and range-separated (HSE06) hybrid functionals, as well as a local basis set, within the CRYSTAL17 code to analyze the relaxed lattice structure, formation energy, magnetic properties, and electronic structures of LiCV and other related isolated defects (LiC V and 2V). Our results reveal that LiCV exhibits three distinct spin states (doublet, quartet, and sextet) with significant differences in spin density distributions on first-neighbor carbon atoms. The quartet state is energetically favored by 0.09 eV and 0.88 eV (B3LYP) compared to the doublet and sextet states, respectively. The Li atom is positioned midway between the two vacancies in the LiCV defect, exhibiting a local D3d symmetry. Our findings reveal that the LiCV defect exhibits remarkable stability within the diamond matrix, with its dissociation into LiC and a vacancy (V) demanding a substantial energy barrier of 6.07 eV. In environments rich in vacancies, LiC shows a strong preference for binding with these vacancies, thereby facilitating the formation of LiCV complexes. Raman scattering calculations offer intriguing insights into the LiCV defect, revealing distinctive spectral features that significantly aid in distinguishing this particular defect among isolated lithium LiC and vacancy (V) defects. This observation is crucial, especially considering the challenges in fabricating shallow donors involving interstitial lithium in diamond, where preexisting vacancies can significantly influence the process. The comprehensive analysis provided in this study not only deepens our understanding of the LiCV defect and its physical properties but also enhances our ability to detect this defect during the synthetic process, and to precisely control the formation conditions. This capability is vital for optimizing the electronic properties of diamond for advanced technological applications. [ABSTRACT FROM AUTHOR]

[Display omitted] With the rapid development of optics and nanotechnology, optical therapy is recognized as a potential strategy to combat bacterial drug resistance. Unfortunately, the limitation of band structure on the therapeutic effect of photocatalytic nano-antimicrobial materials has become a major challenge in the development of optical therapy. Here, Co 9 S 8 and Co 9 S 8 -T200 were prepared by facet engineering design with major exposed facets (311) and (222), respectively. The experimental results demonstrate that the antimicrobial ability of Co 9 S 8 -T200 was significantly higher than that of Co 9 S 8 under the excitation of near-infrared light. Theoretical calculations show that the (222) facets can modulate the d-band center of Co 9 S 8 -T200 closer to the Fermi energy level. This promotes the binding of the intermediate to the active site. The strong adsorption capacity for O 2 and H 2 O and the high efficiency of electron-hole pair separation facilitate the production of reactive oxygen species dominated by singlet oxygen, and the photocatalytic therapy is effectively enhanced. In addition, Co 9 S 8 -T200 has a narrow bandgap to promote photothermal conversion efficiency and light absorption capacity and exhibits excellent photothermal therapy. This work expands new ideas for the development of superior optical antimicrobial agents with synergistic photothermal and photocatalytic therapy. [ABSTRACT FROM AUTHOR]

This article adopts the first principles calculation method to study the defects of La doped ZnO, and analyzes the different occupying defects of La in ZnO: the formation energy, energy band, and density of states of substitution and interstitial defects. It has been proven that during the growth process of La doped ZnO, the possibility of La atoms replacing of Zn atoms to form substitution site defects is greater than La atoms entering the interstitial site to form interstitial site defects. When forming substitution site defects, choosing an oxygen rich growth environment is better than the zinc rich growth environment. Substitution site defects help improve the conductivity of ZnO and improve its performance. The research results of this article can provide a certain theoretical reference for the experimental phenomena and application directions of La doped ZnO. [ABSTRACT FROM AUTHOR]

The density functional theory calculations were conducted to explore the impacts of the incorporation of the Au metals on the adsorption capabilities of MoTe2 toward thiol based S containing molecules. The most favorable positioning of Au atom is on the hollow site of MoTe2 above three Te atoms, which gives rise to the coordination between Au and Se atoms. Most of the adsorption events focus on the substantial interaction between the S atom of considered organic molecules and the surface Au atom, which are fully described and interpreted based on the charge density and density of states plots. Thus, the favorite adsorption model for all the organic molecules is the adsorption based on strong Au-S mutual interactions. The primary aim in this work is to develop a theoretical basis to expose the potential talents of Au-MoTe2 based nanosheets for use in smart sensors of thiol based organic molecules. [ABSTRACT FROM AUTHOR]

Abstract Exploration of metastable phases holds profound implications for functional materials. Herein, we engineer the metastable phase to enhance the thermoelectric performance of germanium selenide (GeSe) through tailoring the chemical bonding mechanism. Initially, AgInTe2 alloying fosters a transition from stable orthorhombic to metastable rhombohedral phase in GeSe by substantially promoting p‐state electron bonding to form metavalent bonding (MVB). Besides, extra Pb is employed to prevent a transition into a stable hexagonal phase at elevated temperatures by moderately enhancing the degree of MVB. The stabilization of the metastable rhombohedral phase generates an optimized bandgap, sharpened valence band edge, and stimulative band convergence compared to stable phases. This leads to decent carrier concentration, improved carrier mobility, and enhanced density‐of‐state effective mass, culminating in a superior power factor. Moreover, lattice thermal conductivity is suppressed by pronounced lattice anharmonicity, low sound velocity, and strong phonon scattering induced by multiple defects. Consequently, a maximum zT of 1.0 at 773 K is achieved in (Ge0.98Pb0.02Se)0.875(AgInTe2)0.125, resulting in a maximum energy conversion efficiency of 4.90% under the temperature difference of 500 K. This work underscores the significance of regulating MVB to stabilize metastable phases in chalcogenides.

Hydrogen evolution reaction (HER) from seawater electrolysis still faces challenges of low reactivity and chloride ions poison at the active sites, leading to reduced efficiency and stability of electrocatalysts. This study presents edge dislocation strategy aimed at inducing lattice strain in ferric oxide through Mo doping, consequently regulating the catalyst's band structure. Through in situ characterizations and DFT analysis, it is confirmed that lattice strain effectively modulates the band structure, intensifies the hybridization between Mo(d)‐Fe(d)‐O(p) orbitals, thereby accelerating the charge transfer rate of HER. Furthermore, band structure modulated by lattice strain enhances water adsorption capacity, reduces the adsorption energy of Cl−, and optimizes the hydrogen adsorption‐free energy (ΔGH*) for HER. Benefiting from above, the optimized 2%‐Mo‐Fe2O3 catalyst demonstrates HER activity and stability in alkaline seawater electrolysis comparable to that of commercial Pt/C. Additionally, the assembled electrolytic cell utilizing an anion exchange membrane (AEM) maintains long‐term stability for >100 h at 500 mA cm−2, showcasing a sustained catalytic effect. [ABSTRACT FROM AUTHOR]

Acoustic topological insulators have the excellent characteristic of the pseudospin-dependent one-way transmission of sound edge states immune to backscattering. We realize the broadband acoustic pseudospin topological edge states with subwavelength generalized topological insulators, which is achieved by reverse pseudospin-orbit coupling. The subwavelength band and broadband nontrivial bandgap can be achieved by adjusting the topological structure of the scatterers and introducing resonators. The results demonstrate that the resonator can significantly reduce the frequencies of p-states and dstates by introducing resonance scattering; the scattering size and rotation angles change the frequencies of p-states and d-states in opposite directions by adjusting the distribution of the sound field. Then, we experimentally realize the pseudospin-dependent one-way transmission of sound edge states along the interface separating phononic crystals with distinct topological phases. Our research provides a systematic scheme for the design of acoustic topological insulators with versatile applications. [ABSTRACT FROM AUTHOR]

Strain engineering serves as an effective method for optimizing electronic and optical properties in semiconductor devices, with applications including the enhancement of optical emission in Ge and GeSn‐based devices, improvement of carrier mobility, and second harmonic generation in silicon photonics structures. Current methods for deformation characterization in semiconductors, such as X‐ray diffraction and Raman spectroscopy, often require bulky and expensive setups and are limited in vertical resolution. Consequently, techniques capable of measuring lattice strain while overcoming these drawbacks are highly desirable. This study proposes a proof of concept for a cost‐effective, compact, fast, and non‐destructive approach to probe non‐uniform strain fields and additional material properties by exploiting the bulk photovoltage effect. The method is benchmarked with an array of silicon nitride stripes deposited under varying pressure conditions on a germanium substrate. Initially, their surface strains are verified through Raman spectroscopy. The deformations are replicated in a finite element method platform by integrating mechanical simulations with deformation potential theory, thereby estimating the band edge energy landscape. Finally, the study discusses the theoretical behavior of the photovoltage signal, considering semiconductor properties, defects, doping, and deformation. The findings offer insights into the development of advanced techniques for strain and transport analysis in semiconductor materials. [ABSTRACT FROM AUTHOR]

In this paper, the structure and electronic properties of InP/PtS 2 heterojunction as well as the photocatalytic and solar hydrogen production efficiency are studied by first principles. Studies have shown that InP/PtS 2 heterojunction is type II band alignment, typical Z heterostructure, has strong light absorption coefficient in the absorption spectrumand, InP/PtS 2 heterojunction with an indirect bandgap of 1.97 eV，the band edge positions that meet the energy band prerequisites for water splitting across different pH levels，The band edge positions and light absorption capabilities have been modified through biaxial strain, with tensile strain enhancing the absorption capacity within the visible light spectrum ranging from 450 to 800 nm(nm). The InP/PtS 2 heterojunction achieves a solar-to-hydrogen conversion efficiency (ηSTH) of 32.5%, which is higher than that of most heterojunctions. The InP/PtS 2 heterojunction is anticipated to emerge as a promising contender for the next generation of photocatalysts. InP/PtS 2 heterojunction is a typical direct Z-scheme heterojunction, which can change its electronic and optical properties under strain, and may contribute to the fields of water splitting. The solar-to-hydrogen efficiency of the InP/PtS2 heterostructure can reached 32.5%. The absorption coefficient in the visible range is enhanced by the application of strain. [Display omitted] • Compared with InP monolayer and PtS 2 monolayer, InP/PtS 2 heterojunctions have better visible light absorption efficiency. • The InP/PtS 2 heterojunction achieves a solar-to-hydrogen conversion efficiency (ηSTH) of 32.5%, which is higher than that of most heterojunctions. [ABSTRACT FROM AUTHOR]

In this study, density functional theory (DFT) calculations within the generalized gradient approximations (GGA) were employed to investigate the structural and electronic properties of CrX2 (X = S, Se, Te) monolayers in the octahedral (1T) phase using Quantum ESPRESSO. The influence of adsorbed OH groups on these properties was also examined. The calculations reveal that bond lengths, curvatures, and lattice constants increase with increasing chalcogen atomic number (X), while structural stability decreases. Interestingly, OH group adsorption lowers the total energy for all CrX2 monolayers, indicating enhanced stability, with the highest stability observed for configurations with two adsorbed OH groups. Furthermore, the electronic properties were studied by analyzing the band structures of CrX2 monolayers with and without OH groups across non-magnetic, ferromagnetic, and antiferromagnetic states. While pristine monolayers exhibit metallic behavior in all magnetic states, the introduction of OH groups leads to diverse electronic behaviors. Additionally, the stable magnetic phases of the monolayers were determined in the presence and absence of OH groups. [ABSTRACT FROM AUTHOR]

The structural stability, electronic structure, and optical properties of the novel YxGd1-xN ternary alloys were studied using the FP-LAPW method with the generalized gradient approximation + Hubbard U (GGA + U). Our results reveal that YxGd1-xN alloys can be experimentally synthesized because they exhibit energetic and mechanical stability. All these systems present semiconducting behavior. Both GdN and YN are indirect band gap semiconductors while YxGd1-xN alloys are direct band gap semiconductors for $x = 0.25\comma \; 0.5\comma \; 0.75$ x = 0.25 , 0.5 , 0.75 because of hybridization between d (Y) and Gd(f) orbitals in the vicinity of the Fermi energy level. The f-d coupling induces the major magnetic moments on the Gd atom. The absorption spectra are reasonably high (>105 cm−1) and the bandgap energy and structure spacing match between YN and GaN which made YxGd1-xN alloys suitable for optoelectronic applications. In the absence of experimental work, our results can be useful for further studies. [ABSTRACT FROM AUTHOR]

This study presents a comprehensive investigation into the electronic properties of Hydroxyapatite (HAp) doped with Zinc (Zn) and Cobalt (Co). Five distinct compositions, denoted as 0.15Zn-HAp, 0.15Co-0.15Zn-HAp, 0.30Co-0.15Zn-HAp, 0.45Co-0.15Zn-HAp, and 0.6Co-0.15Zn-HAp (at%,) have been systematically studied employing Density of States (DOS) and band structure calculations. The computed band gap values for these compositions were determined to be 4.6663, 4.6888, 4.7049, 4.7159, and 4.7082 eV, respectively. These results illuminate the profound influence of Zn and Co doping on the electronic structure of Hydroxyapatite. These findings hold significant implications for the potential applications of these materials in diverse technological and biomedical domains. The systematic approach and precise electronic property characterizations presented in this study provide a robust foundation for further advancements in the realm of advanced materials, with particular relevance to the development of innovative materials for use in cutting-edge technologies and medical applications. [ABSTRACT FROM AUTHOR]

This study is aimed to investigate the effects of introducing dysprosium (Dy) into Zn-based hydroxyapatite (HAp) at various concentrations (0.45, 0.90, 1.35 and 1.80%). The structural and optical properties of pure and doped HAp were thoroughly examined through theoretical and empirical analyses, including X-ray diffraction, Raman spectroscopy and Fourier transform infrared (FTIR) studies. The results confirmed the successful incorporation of Dy into the HAp lattice without significantly affecting its thermal stability or stoichiometry. The introduction of Dy into Zn-based HAp led to notable alterations in several material parameters. The lattice parameters, crystallinity, lattice stress, strain and anisotropic energy density varied with different Dy concentrations. In comparison with undoped HAp, all Dy-doped Zn-based HAps exhibited reduced crystallite size values, indicating a change in the microstructure. Furthermore, the material density increased from 3.159 to 3.228 g cm−3 with Dy doping. The band gap (BG), an important parameter for optical applications, is consistently decreased from 4.6 to 3.9 eV as the Dy concentration increased. This decrease in BG suggests the potential for improved photocatalytic or optoelectronic properties in Dy-doped Zn-based HAp. Additionally, the linear absorption coefficient (LAC) increased, indicating enhanced light absorption. Overall, this study provides a comprehensive understanding of structural and optical modifications induced by Dy doping in Zn-based HAp. These findings contribute to the potential application of Dy-doped Zn-based HAp in various fields, including biomedicine, photocatalysis and optoelectronics. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) perovskites in the Ruddlesden Popper (RP) structure are commonly employed in optoelectronic applications. This research introduces BA2PbBr4-xClx (x=0, 2, and 4) as a mixed-halide 2D perovskite material for use in the active layer of perovskite light-emitting diodes (PeLEDs). By utilizing density functional theory (DFT), the electrical, optical, and stability properties of BA2PbBr4-xClx, which have not been previously reported, are investigated. The results show that with an increasing value of x, the bandgap energy shifts towards higher energies (blue shift), while the refractive index decreases. In addition, we demonstrate the band-edge orbitals by analyzing the partial density of states (PDOS) and observing the effect of halide change on them. In the case of x=0 (BA2PbBr4), the thermodynamic stability is lower compared to the other two states: BA2PbBr4Cl2 (x=2) and BA2PbCl4 (x=4). The thermal stability of these materials is studied using the ab initio molecular dynamic (AIMD) method. Furthermore, the stability of these materials in relation to water is also investigated, aligning with the results of thermodynamic stability. The research also explores the influence of strain on bandgap and refractive index. The results show that all three materials are thermodynamically stable, with direct and large band gaps suitable for blue PeLED applications. [ABSTRACT FROM AUTHOR]

In this paper, electronic properties of Janus MSX monolayers (M = Mo, W; X = Se or Te), including electron energy loss near edge structures (ELNES), as K and L2,3 edge spectra of sulfur atoms, have been calculated using a full potential scheme and the augmented plane wave plus local orbitals (APW+lo) method in the framework of density functional theory (DFT). Due to the lack of experimental results, the obtained spectra are compared with the corresponding spectra of MoS2 monolayer. The band structure analysis shows that the Janus MoSSe and WSSe monolayers are direct bandgap semiconductors, while the Janus MoSTe and WSTe monolayers are indirect bandgap semiconductors. In comparison to MoS2, the main structures of the K edge ELNES spectra of sulfur atoms in Janus monolayers occur at lower energies, due to the structural change and increased bond length. The relative reduction of intensities in the main structures predicts the possibility of reducing the number of partial densities of states (PDOS), that is, the reduced p PDOS for the K edge in the corresponding energy range. In the K (L2,3) edge ELNES spectra of the sulfur atom in Janus monolayers and MoS2 monolayers, the main structures are due to the electron transfer to the unoccupied px+py and pz states (3s of sulfur and 4d states of the transition metal). [ABSTRACT FROM AUTHOR]

The theoretical expectation of semi‐polar light emitting diodes (LEDs) is reviewed and compared it to the experimental data. The reported peak internal quantum efficiency (IQE) of non‐polar, and semi‐polar InGaN LEDs are always much lower than the standard polar (0001) oriented LEDs. Calculating the band structure and states including the n‐ and p‐doped layer of LEDs in many orientations, It is found that the inverted polarization‐induced fields for most common semi‐polar orientations like (112¯$\bar{2}$2) or (202¯${\bar{2}}$1) causes the hole ground state to leak out of the quantum well (QW) into the p‐doped GaN above and by this a low wavefunction overlap and a strongly increased probability for non‐radiative recombination with point defect outside the QW. Based on the calculations, (112¯$\bar{2}$1), (101¯$\bar{1}$2), or (101¯$\bar{1}$3) are predicted as best candidates for LEDs with higher IQE at higher current densities than (0001). LEDs in the uncommon semi‐polar (101¯$\bar{1}$3) orientation on sapphire have been realized. The (101¯$\bar{1}$3) LEDs showed the same IQE as (0001) LEDs but at a much higher current density due to the higher overlap of electron and hole wave functions, which is especially useful for micro‐LEDs. [ABSTRACT FROM AUTHOR]

Using density functional theory and Boltzmann equations, this study calculates and compares the electronic, optical, thermoelectric, and thermodynamic properties of bulk and single-layer germanium carbide structures. It has been shown that germanium carbide in the bulk structure has an indirect energy band gap of 1.61 eV. In a single layer structure, it is a metal. Thermodynamic properties including specific heat at constant volume have been investigated using the quasi-harmonic approximation (QHA) package in QE. According to the studies conducted on optical properties, this material shows good reflection in the visible region. In addition, this structure has high electrical conductivity and low thermal conductivity, which is essential for thermoelectric materials. Thermoelectric calculations using semi-classical Boltzmann transfer theory show that the performance of two-dimensional compounds with graphene gives good thermoelectric results. At 100 K, the highest figure of merit (ZT) for GeC is 1.00. Our findings evaluate the GeC compound as a suitable thermoelectric material in the temperature gradient from 100 to 900 K. [ABSTRACT FROM AUTHOR]

This research applies Density Functional Theory (DFT) to investigate the density of states (DOSs) and band structure and of α-graphyne nanoribbon (α-GYNRs) with 1 × 3 × 3 supercells. For this purpose, the GGA-PBE approximation and Non-equilibrium Green's Function (NEGF) approach are employed. A single carbon atom is removed to simulate the vacancy defect on the nanoribbon. According to the results, unlike α-graphene nanosheet, which has a band gap of 0 eV and is a semimetal, pure α-GYNRs has a band gap of 0.49 eV and is a semiconductor. Removing a carbon atom at 7 different points of α-GYNRs and creating a vacancy lowers the band gap significantly. The band gap in some structures is close to zero, which can be considered pseudo-metals. In addition, the DOS plots show that the height and number of peaks at energies 0 to –5 eV are higher than at energies 0 to +5 eV. Furthermore, the band gap due to the created vacancy directly depends on the vacancy position of the nanoribbon. Hence, the single-atom vacancy (SAV) defect in the α-graphyne nanostructure can lead to a subsurface structural rearrangement. Accordingly, it can be an important parameter in tuning the electronic characteristics of α-GYNRs structures. [ABSTRACT FROM AUTHOR]

The interaction of H, H2, and MgH2 with graphene is investigated using the density functional theory to explore the possibility of exploiting graphene or functionalized graphene as a hydrogen storage medium. The H atom is positioned at various distances from the graphene surface and the energetics are computed in detail. The extent of interaction of the s electron of H with graphene's pz electrons is well brought out. Similar investigations are carried out for H2, MgH2. In the case of H atom, a HC covalent bond is formed. This process turns out to be a prerequisite for proton transfer through graphene. Interactions of H2 and MgH2 with graphene are different from that of H. It leads to the conclusion that functionalized graphene will better substrate/candidate for applications like hydrogen storage. [ABSTRACT FROM AUTHOR]

Zintl materials have received enormous attention in recent time due to their unique structure and thermoelectric efficiency. In this work, quaternary Zintl compounds LaAgZnX2 (X = P, As) have been comprehensively investigated using the FP-LAPW + lo method through first principles approximation. The dynamic stability of the samples is performed through phonon analysis. Birch–Murnaghan equation of states is used to determine ground state parameters. The lattice constant increases while formation energy and bulk modulus B(GPa) decrease by anion replacement from P to As. Band structure calculation shows that LaAgZnP2 is an indirect bandgap semiconductor while LaAgZnAs2 is a direct bandgap semiconductor. The density of states (DOS) demonstrates that the valence band (V.B) is mainly comprised of Zn-d and X-p states while the La-f state is in the conduction band (C.B) along with the minor contribution of the La-d state. Substantial absorption is observed in the low-frequency ultraviolet and visible spectrums for these compounds. Red shifting of the hallmark optic peak occurs due to the anion replacement from P to As. To investigate the electric and thermal conductivities, Seebeck coefficients, and thermopower factor, the Boltzmann transport theory is used to quantify them for these materials. High absorption peaks and figures of merits of these compounds highlight their potential usage in optoelectronics and thermoelectric systems. [ABSTRACT FROM AUTHOR]

The comprehensive first-principles analysis of Ba4Sb4Se11 and [Ba4Sb4Se11]:Sr3+ Selenoantimonate Using DFT demonstrates its semiconductor nature, anisotropic ductile properties, and prospective optoelectronic applications, particularly in solar cells and LED technologies, supported by comprehensive structural, electronic, optical, and mechanical studies. All the relevant parameters were determined in this investigation using the framework of DFT by modified Becke Johnson approximations. These parameters include the extinction coefficient, absorption coefficient, energy loss function, reflectivity, refractive index, optical conductivity, and birefringes. The elastic parameters have been calculated based on anisotropic sound velocities and mechanical stability. These parameters include bulk modulus, shear modulus, Young's modulus, and Poisson's ratio. Based on an analysis of the energy band dispersions, it can be concluded that the examined compounds possess semiconductor properties. The data on elastic parameters suggest that the material exhibits anisotropic and ductile characteristics, which could have potential applications in optoelectronics. The Ba4Sb4Se11 (2.2 eV) and [Ba4Sb4Se11]: Sr3+ (1.68 eV) have a direct band gap, which falls within the visible spectrum showing semiconducting nature. The analysis of the thermoelectric properties of investigated compounds has been conducted using the Boltztrap code, marking a significant in scientific research. The study revealed that these compounds have the potential to be utilized in highly challenging transport conditions. Additional investigations and cooperation are essential for understanding the fundamental processes and enhancing the material for effective utilization in various technological applications for solar cells and LED in the energy and optoelectronic industry. [ABSTRACT FROM AUTHOR]

A series of Cu12-xGaxSb4S13 (x=0,0.05,0.1 and 0.15) samples were synthesized through high-temperature melting method and heat annealing technique combined with spark plasma sintering (SPS). The phase composition, band structure and thermoelectric properties of the samples were characterized and analyzed. The results show that Ga doping can introduce impurity band near the conduction band, acting as donor energy level, thus reducing the hole carrier concentration and increasing the Seebeck coefficient of the samples. At the same time, with the increase of Ga doping content, the thermal conductivity of Ga-doped samples decreases significantly. When the temperature is 770 K, the thermal conductivity of Cu11.85Ga0.15Sb4S13 sample decreases to 1.20 W/mK, which is 29% lower than that of the intrinsic material. Finally, the maximum ZT value of 0.7 is achieved for Cu11.9Ga0.1Sb4S13 sample at 770 K, a 40% improvement over the intrinsic Cu12Sb4S13. [ABSTRACT FROM AUTHOR]

Aiming to efficiently expedite alkaline overall water splitting (OWS) by addressing challenges such as sluggish kinetics and limited stability, a hollow Fe‐doped Ni(OH)2‐NiS@Ni(OH)2 nanorod array with surface nanosheets is devised, featuring a high‐index Fe‐doped Ni(OH)2(101)‐NiS(211) heterostructural interface and an upshifted d‐band center. This nanoarchitecture intensifies the adsorption and interaction of H2O and OH− reactants on the electrocatalyst surface, suitably bonds the *H intermediate in hydrogen evolution reaction (HER) and accelerates electron movement of *H, minimizes the energy requirement of the rate‐limiting phase (*OH → *O) in oxygen evolution reaction (OER) by facilitating O─H cleavage of *OH and optimally adsorbs *O, amplifies the exposure of surface‐active centers, and ultimately reduces the apparent activation energy. Consequently, the overpotentials are as low as 66.4 mV (HER) and 254.9 mV (OER) at 10 mA cm−2, alongside high turnover frequencies of 142 s−1 (H2) and 279 s−1 (O2) at 100 and 300 mV, respectively, markedly outperforming direct‐electrodeposited analogues. When functioning as a bifunctional electrode in OWS, this material merely requires 1.57 V at 10 mA cm−2 and sustains an operation for 168 h, approaching Pt/C||RuO2 benchmark. [ABSTRACT FROM AUTHOR]

As a most promising environmental technology, the substantial enhancement of photocatalytic efficiency is still a big challenge for practical applications. In this work, the surface of Bi2O2CO3 (BOC) nanotubes are modified by Cl and I. The as-obtained samples at different hydrothermal temperatures (T) are designated as T-X-BOC (X = Cl, I). X-ray diffraction (XRD), energy dispersive X-ray (EDX) spectroscopy and X-ray photoelectron spectroscopy (XPS) prove that Cl and I merely chemically adsorb on the BOC surface, rather than dope into the crystal lattice. The surface modification of Cl and I slightly increases light absorption range, while significantly promotes the photoelectron migration from bulk to the surface that greatly enhances the carrier separation efficiency. Density functional theory (DFT) calculations further prove that surface Cl and I have adjusted band structure and surface charge distribution. Besides, the surface Cl and I favor the O2 adsorption and trap the surface photoelectrons, thus promoting the formation of •O2–; while the surface Cl and I impede the surface adsorption of H2O, thus refraining the generation of •OH. In the degradation of rhodamine B (RhB), holes and •O2− radicals play the crucial role. Under ultraviolet light irradiation (λ < 420 nm) for 45 min, the RhB degradation ratios over 150-Cl-BOC (94%) and 150-I-BOC (85%) are 4.2 and 3.7 times higher than that of original BOC (18%), respectively. This work demonstrates that the simple surface halogenation modification greatly improves the photocatalytic activity. [ABSTRACT FROM AUTHOR]

The magnetic properties, band structure results, and magnetocaloric effect of GdCo1.8M0.2 with M = Fe, Mn, Cu, and Al are reported. The band structure calculations demonstrate that all the samples have a ferrimagnetically ordered ground state, in perfect agreement with the magnetic measurements. Calculated magnetic moments and variation with the alloy composition are strongly influenced by hybridisation mechanisms as sustained by an analysis of the orbital projected local density of states. The XPS measurements reveal no significant shift in the binding energy of the investigated Co core levels with a change in the dopant element. The Co 3s core-level spectra gave us direct evidence of the local magnetic moments on Co sites and an average magnetic moment of 1.3 µB/atom was found, being in good agreement with the theoretical estimation and magnetic measurements. From the Mn 3s core-level spectra, a value of 2.1 µB/Mn was obtained. The symmetric shapes of magnetic entropy changes, the Arrott plots, and the temperature dependence of Landau coefficients clearly indicate a second-order phase transition. The relative cooling power, RCP(S), normalized relative cooling power, RCP(∆S)/∆B, and temperature-averaged entropy change values indicate that these compounds could be promising candidates for applications in magnetic refrigeration devices. [ABSTRACT FROM AUTHOR]

Zintl compounds such as n‐type Mg3(Sb,Bi)2 show promising thermoelectric applications benefiting from their high valley degeneracy and low lattice thermal conductivity. However, the heavier p‐type AMg2X2 (A = Ca, and Yb; X = Bi and Sb) Zintl counterparts even exhibit a higher κlat due to strong chemical bonding. Reducing κlat of AMg2X2 is an important route for improving thermoelectric performance. Herein, it is found that Cd doping at the Mg site in CaMg2Bi2 can weaken intralayer covalent bonds and soften acoustic phonons, as well as fill the optical phonon gap. These effects result in large atomic displacement, low phonon group velocity, and strong lattice vibration anharmonicity. Doping 10% Cd leads to a reduction of 56% in the κlat of CaMg2Bi2. Moreover, Cd doping promotes orbital alignment and thus increases the density‐of‐states effective mass and Seebeck coefficient. Eventually, in conjunction with carrier concentration optimization by Na doping and band structure engineering by Ba doping, a high ZT of ≈1.3 at 873 K in (Ca0.85Ba0.15)0.995Na0.005Mg1.85Cd0.15Bi2 sample is realized. This work highlights the significant role of manipulating chemical bonding in suppressing phonon propagation of semiconductors. [ABSTRACT FROM AUTHOR]

A first-principles method was used to explore the influence of tensile strain on the electrical and optical characteristics of Nb-doped MoSe2. The tensile strain has been discovered to have a higher influence on the electrical structure of the Nb-doped MoSe2 system than pure monolayer MoSe2. According to the energy band structure study, the pure monolayer MoSe2 is a direct bandgap semiconductor, but the system doped with Nb instead of Mo atoms is a p-type-doped semiconductor. The bandgap of the Nb-doped MoSe2 system decreases gradually with the increase of tensile strain, but still maintains the p-type semiconductor properties, and the bandgap of the pure monolayer MoSe2 also decreases gradually with the increase of tensile strain. From the density of states analysis, it is found that for the total density of states of the doped system at different tensile strains, it is mainly contributed by the Mo-4d and Se-4p orbitals. The optical properties analysis showed that the doped system under tensile strain had higher absorption coefficient and reflectance peak than the Nb-doped MoSe2 system without tensile strain. Additionally, the doped system showed redshift phenomenon in both the absorption and reflection peaks as the tensile strain increased. [ABSTRACT FROM AUTHOR]

Improving ferro-piezoelectric properties of niobate-based perovskites is highly desirable for developing eco-friendly high-performance sensors and actuators. Although electro-strain coupling is usually obtained by constructing multiphase boundaries via complex chemical compositions, defect engineering can also create opportunities for novel property and functionality advancements. In this work, a representative tetragonal niobate-based perovskite, i.e., KNbO3, is studied by using first-principles calculations. Two intrinsic types of Nb antisite defect complexes are selected to mimic alkali-deficiency induced excess Nb antisites in experiments. The formation energy, electronic profiles, polarization, and piezoelectric constants are systematically analyzed. It is shown that the structural distortion and chemical heterogeneity around the energetically favorable antisite pair defects, i.e., ( Nb K 4 · + K Nb 4 ′ ), lower the crystal symmetry of KNbO3 from tetragonal to triclinic phase, and facilitate polarization emergence and reorientation to substantially enhance intrinsic ferro-piezoelectricity (i.e., spontaneous polarization Ps of 68.2 μC/cm2 and piezoelectric strain constant d33 of 228.3 pC/N) without complicated doping and alloying. [ABSTRACT FROM AUTHOR]

[Display omitted] In this study, the impact of lead (Pb) doping on the photoelectrochemical (PEC) water splitting performance of tungsten oxide (WO 3) photoanodes was investigated through a combination of experimental and theoretical approaches. Pb-doped WO 3 nanostructured thin films were synthesized hydrothermally, and extensive characterizations were conducted to study their morphologies, band edge, optical and photoelectrochemical properties. Pb-doped WO 3 exhibited efficient carrier density and charge separations by reducing the charge transfer resistance. The 0.96 at% Pb doping shows a record photocurrent of ∼ 1.49 mAcm−2 and ∼ 3.44 mAcm−2 (with the hole scavenger) at 1.23 V vs. RHE besides yielding a high charge separation and Faradaic efficiencies of ∼ 86 % and > 90 %, respectively. A shift in the Fermi level towards the conduction band was also observed upon the Pb doping. Additionally, density functional theory (DFT) simulations demonstrated the changes in the density of states and bandgap upon Pb doping, exhibiting favorable changes in the surface and bulk properties of WO 3. [ABSTRACT FROM AUTHOR]

Context: In this paper, the effects of torsional deformation on the electronic properties of intrinsic WSe2 system and Ca-adsorbed WSe2 system were systematically studied by first-principles method. The results show that Ca can be stably adsorbed on the vacancy (H site) of WSe2 surface in all deformation systems, and the adsorption energy of the system without deformation is the highest. Intrinsic WSe2 is a semiconductor with a direct band gap of 1.53 eV. The torsional deformation makes WSe2 change from a direct band gap semiconductor to an indirect band gap semiconductor and finally to a metal property. The adsorption of Ca makes the conduction band of WSe2 move down and increases the number of peaks in the conduction band region. The new density of state peaks are mainly derived from the contribution of W-d, Se-p, and d orbitals of adsorbed atoms in each adsorption system. Mulliken charge analysis shows that Ca transfers most of the valence electrons to the substrate, and the torsional deformation changes the amount of transferred charge. The twist deformation reduces the diffusion barrier of Ca on WSe2 surface from 0.20 to 0.14 eV. The above results provide a basis for the improved application of WSe2 in ion batteries. Methods: In this study, all the first-principles calculations are based on Materials Studio 8.0 software package. The generalized gradient approximation (GGA) functional Perdew-Burke-Ernzerhof (PBE) is used for the electron exchange correlation interactions in all systems. The optimization algorithm uses Broyden-Fletcher-Goldfarb-Shanno (BFGS) to optimize the model structure and calculate the energy. The measured cutoff energy is optimized to 450 eV, and the radius of the vacuum layer in the Z-axis direction is 20 Å. The K-point of 7 × 7 × 1 is selected by Monkhorst–Pack method. The structural optimization criterion is selected, the convergence radius of the force is 0.01 eV/Å, and the displacement radius between atoms is within 0.001 Å distance. The energy convergence radius of each atom is less than 1.0 × 10−6 eV/atom. [ABSTRACT FROM AUTHOR]

The titanium dioxide (TiO2) semiconductor's wide band gap property restricts its application in a variety of fields. To ensure cost-effectiveness and time efficiency, researchers emphasized material modeling and theoretical analysis. This study employs a Density Functional Theory approach to investigate how the presence of transition metal elements (TME) like rhodium (Rh) and rhenium (Re) affects the optoelectronic properties of TiO2. The study was carried out using the VASP software package and the plane-wave pseudopotential technique. The formation energy, electronic band structure, and optical properties of TiO2 were affected by the addition of both Rh and Re as doping materials. The outcomes of the band structure and total density of states (TDOS), point out notable alterations in the energy gap (Eg) of TiO2. The plot of the band structure illustrates that the introduction of Re leads to a more substantial reduction in the TiO2 band gap compared to Rh. The introduction of numerous sub-states into the band gap causes the valence band to approach the conduction band at the Gamma point. The band gap reduction caused by the addition of Rh and Re TME is confirmed by the relocation of the TDOS to lower energies in the doped TiO2 structure. Furthermore, significant changes in the partial density of states of TiO2 upon Re doping have been observed at the bottom of the conduction band, highlighting the effectiveness of Re doping in modifying the electronic band structure of TiO2. The outcomes of band structure and TDOS proved that TME with high atomic mass is certain to decrease TiO2's band gap to the range required for usage as a photocatalytic material. Rh and Re doping in TiO2 alter their optical properties, making them suitable for optoelectronic devices. [ABSTRACT FROM AUTHOR]

In the present study, we investigate the influence of boron (B) and phosphorus (P) (p- and n-type, respectively) doping on the electronic properties of ultra-thin silicon nanowires (SiNWs) by gradient-corrected density functional calculations with the Perdew–Burke–Ernzerhof (PBE) approximation. In the limit of very small diameters (5–8 Å), both pristine and highly active unsaturated SiNWs with orientations along the [001] and [111] directions exhibit electronic states around the Fermi level, indicative of conductive properties. Conduction is further enhanced by the introduction of doping atoms, as demonstrated by the relative change in the band structures of SiNWs with and without B and P doping. This investigation provides an important insight into the electronic states of SiNWs, which are candidates for future electronics or sensing applications. [ABSTRACT FROM AUTHOR]