Diamond-like Structure Research Articles

Performance and mechanism of the structure formation and physical-mechanical properties of concrete by modification with nanodiamonds

Nanomodifying additives in the building materials production is a relevant and widely studied topic in current building materials science. Nanodiamonds are used in various fields of science and technology. However, they were not used as a modifying additive in the production of building composite materials. The purpose of this study is to investigate the mechanism of interaction of chemically pure cavitation synthesis nanodiamonds (КНА-НС) with cement concrete on the structure formation and mechanical properties of fresh and hardened concrete. These KHA-HC nanodiamonds are carbon sp3 hybridized nanoparticles with a diamond-like structure and a particle size in a cross section of not more than 3 nm, shaped close to spherical and a clear mono modal distribution throughout the entire fractional composition, with a maximum of 1 nm to 3 nm. During the research, the initial components were selected, the compatibility of these components was checked, including the formation of test samples, the properties of fresh concrete, the density of hardened concrete, compressive and flexural strength at various ages of hardening (2, 7, 14 and 28 days) were studied using standard methods, and X-ray diffraction and scanning electron microscopy of concrete were also carried out. It has been established that the addition of KHA-HC accelerates the process of concrete strength gain. The greatest effect was recorded for concrete aged 2 days. With an optimal KHA-HC content of 0.4 %, the increases in compressive and flexural strength were 28.6 % and 26.1 %, respectively. The addition of KHA-HC in all considered ranges from 0.1 % to 1.0 % has a positive effect on the strength properties of concrete. The most effective dosage is 0.4 %. The increases in compressive and flexural strength of concrete at an age of 28 days were 15.1 % and 15.7 %, respectively. Nanomodification of concrete with the KHA-HC additive does not affect the phase composition of concrete. The effect of “self-reinforcement of cement matrix” put forward in this study is confirmed by images of the microstructure of the cement matrix with a large accumulation of calcium hydrosilicate zones.

New Polymorphic Varieties of Boron Nitride with Diamond-Like TA-Type Phases

In this work, a theoretical study of new polymorphic varieties of boron nitride, which have diamond-like structures with boron and nitrogen atoms in equivalent structural positions, was carried out. The model construction of new phases of boron nitride was performed in the process of crosslinking precursor nanostructures. Single-walled boron nitride nanotubes with chirality indices (3;0), (4;0), and (6;0) were chosen as precursors for the model construction of diamond-like phases. Using the density functional theory method in the generalized gradient approximation, the possibility of stable existence of three new structural varieties of boron nitride with a diamond-like structure was established: BN-TA4, BN-TA5, BN-TA6. The structure of the BN-TA7 diamond-like phase turned out to be unstable and, in the process of geometric optimization, was transformed into the initial structure, a boron nitride nanotube (6;0). As a structural characteristic, the bulk density of the new polymorphs was determined, which is in the range from 2.613 to 3.0836 g/cm3. The sublimation energy of new polymorphic varieties ranges from 17.16 to 17.63 eV/(BN). The value of the band gap near the Fermi energy varies from 5.37 to 5.74 eV.

Toward Strong UV-Vis-NIR Second-Harmonic Generation by Dimensionality Engineering of Zinc Thiocyanates.

The precise modulation of the spatial orientations and connection modes of primitives is vital for certain critically important optical functions for nonlinear optical (NLO) materials (specifically, second-harmonic generation (SHG) and optical bandgap); however, we are yet to achieve a sufficient level of control for the designed construction of efficient broadband NLO materials. Exploiting the changes in microscopic polarization that may result from dimensional increase, we propose herein a zero-dimensional (0D)-to-three-dimensional (3D) dimensionality-increase strategy to realize strong broadband SHG responses for the first time. The novel 3D pseudo diamond-like Zn(SCN)2 has been synthesized by removing SHG-inactive [NH4]+ counter cations and H2O molecules that are located between the adjacent discrete [Zn(SCN)4] building blocks within the 0D (NH4)2Zn(SCN)4·3H2O. The 0D-to-3D dimensionality engineering, proceeding from (NH4)2Zn(SCN)4·3H2O to Zn(SCN)2, results in significantly enhanced SHG responses and efficient broadband activity (8 × KH2PO4 @ 1064 nm, 4.18 eV bandgap for the former c.f. 2 × β-BaB2O4 @ 380 nm, 30 × KH2PO4 @ 1064 nm, 2 × KTiOPO4 @ 2100 nm, 4.78 eV bandgap for the latter) from the UV to the NIR regions (SHG@300-1050 nm). Theoretical calculations and crystal structure analyses reveal that the coordination-bond-connected [Zn(SCN)4] building blocks within the diamond-like structure of Zn(SCN)2 are responsible for its giant broadband SHG responses.

Biogenic synthesis of nickel cobaltite nanoparticles via a green route for enhancing the photocatalytic and electrochemical performances

Green synthesis aligns with the global demand for eco-friendly and sustainable technologies, reducing the dependency on harmful chemicals and high-energy processes typically used in conventional synthesis techniques. This study highlights a novel green synthesis route for nickel cobaltite nanoparticles (NiCO2O4 NPs) utilizing Hyphaene thebaica extract as a natural reducing and stabilizing agent. The synthesized NiCO2O4 NPs, with sizes ranging from 20 to 30 nm, exhibited uniform diamond-like structures as confirmed by SEM and TEM imaging. XRD analysis verified the polycrystalline nature of these nanoparticles, while EDS measurements confirmed the elemental composition of Ni and Co. The presence of functional groups was subsequently verified through FT-IR analysis, and Raman spectroscopy further confirmed phase formation. Electrochemical evaluations revealed significant pseudocapacitive behavior, showing a specific capacitance of 519 F/g, demonstrating their potential for high-performance supercapacitors. To further assess the applicability of the synthesized NiCO2O4 NPs, their photocatalytic activity against methylene blue (MB) dye was investigated, resulting in a 99% degradation rate. This impressive photocatalytic efficiency highlights their potential application in environmental remediation. Overall, this work underscores the significant potential of green synthesis methods in producing high-performance nanomaterials while simultaneously reducing environmental impact and promoting sustainable development.

Uniaxial Negative Thermal Expansion in γ-LiBO2 with a Closed-Framework Diamond-Like Structure

Uniaxial Negative Thermal Expansion in γ-LiBO₂ with a Closed-Framework Diamond-Like Structure

Symmetries and wave functions of photons confined in three-dimensional photonic band gap superlattices

We perform a computational study of confined photonic states that appear in a three-dimensional (3D) superlattice of coupled cavities, resulting from a superstructure of intentional defects. The states are isolated from the vacuum by a 3D photonic band gap, using a diamondlike inverse woodpile crystal structure, and they exhibit “Cartesian” hopping of photons in high-symmetry directions. We investigate the confinement dimensionality to verify which states are fully 3D-confined, using a recently developed scaling theory to analyze the influence of the structural parameters of the 3D crystal. We create confinement maps that trace the frequencies of 3D-confined bands for select combinations of key structural parameters, namely the pore radii of the underlying regular crystal and of the defect pores. We find that a certain minimum difference between the regular and defect pore radii is necessary for 3D-confined bands to appear, and that an increasing difference between the defect pore radii from the regular radii supports more 3D-confined bands. In our analysis, we find that their symmetries and spatial distributions are more varied than electronic orbitals known from solid-state physics. We surmise that this difference occurs since the confined photonic orbitals derive from global Bloch states governed by the underlying superlattice structure, whereas single-atom orbitals are localized. Based on this realization, we suggest that the extent symmetries of “photonic orbitals” could possibly translate to novel macroscopic behaviors of “photonic solid-state matter,” never before seen in the standard electronic solid-state systems. We also discover pairs of degenerate 3D-confined bands with p-like orbital shapes and mirror symmetries matching the symmetry of the superlattice. Finally, we investigate the enhancement of the local density of optical states for cavity quantum electrodynamics applications. We find that donorlike superlattices, i.e., where the defect pores are smaller than the regular pores, provide greater enhancement in the air region than acceptorlike structures with larger defect pores, and thus offer better prospects for doping with quantum dots and ultimately for 3D networks of single photons steered across strongly coupled cavities. Published by the American Physical Society 2024

Investigations of TiC and SiC films synthesized by DC magnetron sputtering and thermal annealing

In this research article, two-dimensional thin films of titanium, hierarchical titanium-carbon, titanium carbide, hierarchical silicon-carbon, and silicon carbide films were synthesized on the plates of AISI 304 stainless steel and glass slides, individually, using DC magnetron sputtering techniques. During the sputtering process, the creation of stable plasma was affected by the vacuum level, DC potential, plasma current, and Argon gas. The results showed that the coatings of titanium, titanium-carbon, and titanium carbide modified the optical properties of stainless steel. Additionally, titanium carbide coatings displayed a shiny gold appearance with a hardness of 1500 HV. Besides this, X-ray diffraction studies revealed a hexagonal Ti in the metallic films and C60, and diamond-like structures dispersed on its surface after the carbon coating. The spherical particulates of Ti and C60/diamond-like carbon particulates anchored on its surface were observed using scanning electron microscope analysis. The structural analysis indicated C vacant sites, which are available for ionic/electronic charge diffusion, thereby rendering these structures suitable for making Li storage batteries as electrode material.

Prediction of high-temperature superconductors at ambient pressure with diamond-like structures: B2CX (X = N, P).

In recent years, the superconducting properties of materials with diamond-like structures have attracted widespread attention. The superconducting transition temperature (Tc) of most diamond-like structures is relatively low, and there has been little research on the superconductivity of ternary diamond-like materials. Here, based on first-principles calculations, we predict B2CX (X = N, P) with P3m1 space group, and reveal that they all exhibit phonon-mediated superconductivity at ambient pressure, with Tc range from 44.3 to 46.1 K, which is higher than most diamond-like superconductors. The coupling between metallic σ electrons and softened E phonon (B-C stretching modes) contributes greatly to their superconductivity. Our work provides an important theoretical basis for the experimental design and synthesis of ternary high-temperature superconductors with diamond-like structures.

Formation of two-dimensional diamond-like colloidal crystals using layer-by-layer electrostatic self-assembly.

We report here that a two-dimensional (2D) diamond-like structure of micron-sized colloidal particles can be obtained by layer-by-layer self-assembly. Positively and negatively charged silica particles, 1 μm in diameter, were used in the experiments. On a positively charged, flat glass substrate, the first layer of negatively charged particles was prepared to form a non-close-packed 2D crystal. Then the second and third layers were fabricated using electrostatic adsorption. The positions of adsorbed particles were controllable by tuning the zeta-potential of the particles and the salt concentration of the medium. The FDTD calculations show that the 2D diamond structures of particles with higher refractive index (titania) have an absorption band in the wavelength range corresponding to the photonic band gap of the 3D bulk crystal. We expect these findings to be useful for the fabrication of novel photonic materials.

Giant thermal conductivity and strain thermal response of nitrogen substituted diamane: a machine-learning-based prediction.

With the ongoing trend of seeking miniaturization and enhanced performance for electronic devices, effective thermal management has emerged as a critical concern. The discovery and investigation of high thermal conductivity (κ) materials have proved to be pivotal in addressing this challenge. This study aims to explore the distinctive properties and potential applications of nitrogen substituted diamane (NCCN), a two-dimensional material with a diamond-like structure composed of carbon and nitrogen atoms. This work systematically delves into NCCN's thermal, mechanical, and electrical properties. It is predicted that NCCN exhibits an exceptional κ, ∼2288 W m-1 K-1, at room temperature (300 K) by combining the machine-learning interatomic potential method and the phonon Boltzmann transport equation, surpassing that of H-diamane and rivaling that of diamond, and an impressive electronic band gap of ∼4.47 eV (PBE). For mechanical properties, the stress-strain relationship reveals that NCCN exhibits isotropic elastic properties and anisotropic tensile strengths. Additionally, the variations in NCCN's κ and electronic energy band structure under different strains underscore its substantial potential in the field of thermoelectric applications.

Excellent Nonlinear Optical M[M4 Cl][Ga11 S20 ] (M = A/Ba, A = K, Rb) Achieved by Unusual Cationic Substitution Strategy.

The typical chalcopyrite AgGaQ2 (Q = S, Se) are commercial infrared (IR) second-order nonlinear optical (NLO) materials; however, they suffer from unexpected laser-induced damage thresholds (LIDTs) primairy due to their narrow band gaps. Herein, what sets this apart from previously reported chemical substitutions is the utilization of an unusual cationic substitution strategy, represented by [[SZn4 ]S12 + [S4 Zn13 ]S24 + 11ZnS4 ⇒ MS12 + [M4 Cl]S24 + 11GaS4 ], in which the covalent Sx Zny units in the diamond-like sphalerite ZnS are synergistically replaced by cationic Mx Cly units, resulting in two novel salt-inclusion sulfides, M[M4 Cl][Ga11 S20 ] (M = A/Ba, A = K, 1; Rb, 2). As expected, the introduction of mixed cations in the GaS4 anionic frameworks of 1 and 2 leads to wide band gaps (3.04 and 3.01 eV), which exceeds the value of AgGaS2 , facilitating the improvement of high LIDTs (9.4 and 10.3 × AgGaS2 @1.06 µm, respectively). Furthermore, compounds 1 and 2 exhibit moderate second-harmonic generation intensities (0.84 and 0.78 × AgGaS2 @2.9 µm, respectively), mainly originating from the orderly packing tetrahedral GaS4 units. Importantly, this study demonstrates the successful application of the cationic substitution strategy based on diamond-like structures to provide a feasible chemical design insight for constructing high-performance NLO materials.

Review on detection method, main source and geological application of diamondoids in crude oil

Diamondoids are alkanes with cage-like structure. Their diamond-like structure makes them have high stability and anti-biodegradability, and can be preserved and enriched in complex and long geological processes. Therefore, the continuous development of quantitative detection methods for diamondoids in crude oil has deepened the research of these compounds and made them more widely used in crude oil cracking evaluation, maturity evaluation, biodegradation evaluation and other aspects.

Synthesis, Crystal Structure, and Nonlinear-Optical Properties of a Diamond-Like Chalcogenide Cu2GeS3.

Metal sulfides with diamond-like (DL) structures generally exhibit excellent mid-IR nonlinear-optical (NLO) properties. Here, Cu2GeS3 (CGS) as a member of the DL chalcogenides was synthesized by a high-temperature solid-state method, and the optical properties were carefully studied experimentally and theoretically. The results revealed that CGS has a large second harmonic generation (0.8 × AgGaSe2) and a moderate birefringence of 0.067 at 1064 nm. In addition, the linear and NLO properties of the A2MS3 (A = Cu, Li; M = Ge, Si) series of compounds were evaluated and compared with the help of first-principles calculations.

Structure Evolution and Bonding Inhomogeneity toward High Thermoelectric Performance in Cu2CoSnS4-xSex Materials.

Lightweight diamond-like structure (DLS) materials are excellent candidates for thermoelectric (TE) applications due to their low costs, eco-friendly nature, and property stability. The main obstacles restricting the energy-conversion performance by the lightweight DLS materials are high lattice thermal conductivity and relatively low carrier mobility. By investigating the anion substitution effect on the structural, microstructural, electronic, and thermal properties of Cu2CoSnS4-xSex, we show that the simultaneous enhancement of the crystal symmetry and bonding inhomogeneity engineering are effective approaches to enhance the TE performance in lightweight DLS materials. Particularly, the increase of x in Cu2CoSnS4-xSex makes the DLS structure with the ideal tetrahedral bond angles of 109.5° favorable, leading to better crystal symmetry and higher carrier mobility in samples with higher selenium content. In turn, the phonon transport in the investigated DLS materials is strongly disturbed due to the bonding inhomogeneity between anions and three sorts of cations inducing large lattice anharmonicity. The increase of Se content in Cu2CoSnS4-xSex only intensified this effect resulting in a lower lattice component of the thermal conductivity (κL) for Se-rich samples. As a result of the enhanced power factor S2ρ-1 and the low κL, the dimensionless thermoelectric figure of merit ZT achieves a high value of 0.75 for Cu2CoSnSe4 DLS material. This work demonstrates that crystal symmetry and bonding inhomogeneity play an important role in the transport properties of DLS materials and provide a path for the development of new perspective materials for TE energy conversion.

Bounds on the Poisson's ratios of diamond-like structures

Abstract Poisson's ratios of diamond-like structures, such as cubic C, Si, and Ge, have been widely explored because of their potential applications in solid-state devices. However, the theoretical bounds on the Poisson's ratios of diamond-like structures remain unknown. In this paper, we have derived analytical expressions for the minimum and maximum Poisson's ratios, as well as the Poisson's ratios averaged by three different schemes (i.e., Voigt, Reuss, and Hill averaging schemes). These expressions are based on the correlation between macroscopic elastic constants and microscopic force constants of diamond-like structures, and are solely a function of a dimensionless quantity (λ) that characterizes the ratio of mechanical resistances between angle bending and bond stretching. Based on these expressions, we have determined the bounds on the Poisson's ratios, as well as the minimum and maximum Poisson's ratios, and the Poisson's ratios averaged by the three schemes mentioned above. Specifically, these bounds are (−1, 4/5), (−1, 1/5), (0, 4/5), (−1, 1/2), (−1/3, 1/2), and (−2/3, 1/2), respectively. These results were well supported by atomistic simulations. Mechanism analyses demonstrated that the diverse Poisson's behaviors of diamond-like structures result from the interplay between two deformation modes (i.e., bond stretching and angle bending). This work provides the roadmap for finding interesting Poisson's behaviors of diamond-like structures.

Development of phase pure Cu2ZnSiSe4 via solid state synthesis for energy applications

In recent years, quaternary diamond-like metal chalcogenide semiconductor nanocrystals have received a lot of attention in solar cell and thermoelectric applications. The optoelectronic properties of quaternary diamond-like structures are influenced by their crystal structure. In this work, a series of experiments have been performed to understand the crystal system of Cu2ZnSiSe4 materials via solid state synthesis, namely mechanosynthesis to get a single phase of quaternary chalcogenide via single step route synthesis. The materials were performed at different milling time to study the single phase compound and phase transformation of the materials. Based on the theory and existing literature, the composition of the materials has been selected as 2:1:1:4 which is the optimum composition for quaternary chalcogenides. Based on the composition, the material properties will be changed. X-ray diffraction (XRD) and Raman spectroscopy were used to analyse the structure and phase purity of Cu2ZnSiSe4 nanoparticles. Field emission scanning electron microscopy (FESEM) and Energy dispersive X-ray spectroscopy (EDS) results showed that the average size of the Cu2ZnSiSe4 particles and the composition of products were close to the stoichiometry of Cu2ZnSiSe4. Optical studies show that Cu2ZnSiSe4 nanocrystals exhibit good, strong optical absorption in the visible region of the electromagnetic spectrum and a 1.12 eV bandgap. Hall measurement shows the bulk property of the materials and it is inferred that the synthesized materials show p-type conductivity in bulk. The obtained compound possesses good structural and optoelectronic behavior and hence could be utilized as effective solar absorber in thin film solar cells.

Introducing Novel Materials with Diffuse Electrons for Applications in Redox Catalysis and Quantum Computing via Theoretical Calculations

Diamond-like structures, where carbon atoms have been replaced with Li+ and C–C bonds with diamines, have currently been introduced as new materials, which can host diffuse electrons in the periphery of each lithium tetra-amine center. These materials display a diverse range of properties behaving as metals or semiconductors depending on the diamine chain length. Multi-reference wavefunction and density functional theory calculations were employed to study the electronic structure of these materials. Initially, gas phase calculations are performed on isolated (NH3)3LiNH2(CH2)1–10H2NLi(NH3)3 molecular strings. One diffuse electron surrounds the periphery of each −NH2Li(NH3)3 terminus. The two terminal electrons couple into a triplet and open-shell singlet states, which are nearly degenerate for long chains and as closed shell singlets for short. At intermediate lengths, the wavefunction of the ground-state singlet state mixes both open- and closed-shell configurations raising doubts about which configuration should be considered for density functional theory calculations. Observations from gas phase calculations accurately predict properties from the condense phase density functional theory calculations carried out for proposed crystalline Li-diamine materials, offering an avenue for further development and insight. Spin-polarized and unpolarized calculations are performed for the whole range of hydrocarbon sizes reporting geometrical and electronic band structures, spin density contours, and density of states. Diffuse electrons can be used for redox reactions or can serve as qubits for quantum computing. Future work will focus on decorating the hydrocarbon backbone with functional groups and/or bulky units, in order to facilitate or block the association between neighboring electrons for more controlled quantum computing applications and propose materials for selective redox catalysis.

Solid Carbon Products of Isobutane Decomposition in Laser Plasma

In this work, the properties of carbon films fabricated upon the action of laser plasma on the simple gaseous hydrocarbons have been studied. The change in the properties of these films caused by subsequent thermal or laser treatment has been investigated. Carbon films deposited on a cold substrate have a complex nature, which is similar to the nature of tholins. These films contain carbon atoms in the sp2- and sp3-hybrid states in proportional amounts, as well as various structural fragments containing hydrogen and oxygen. Thermal annealing of carbon films leads to a decrease in the concentration of hydrogen and oxygen-containing structures, unification of the structure based on carbon atoms in sp3 hybridization and formation of a so-called diamond-like structure. It was shown that carbon films are formed by spherical particles with an average diameter of 7–8 nm. Laser annealing and fabrication of a film with direct constant laser exposure leads to formation of a graphene-like structure meaning sp2 hybridization of carbon.

Peroxymonosulfate Activation by Different Synthesized CuFe-MOFs: Application for Dye, Drugs, and Pathogen Removal

In this study, three CuFe-MOFs were successfully synthesized by a solvothermal process by changing the ratio of solvents, salts, or temperature. These MOFs named CuFe(BDC-NH2)R, CuFe(BDC-NH2)S, and CuFe(BDC-NH2)D showed rod-shaped, spindle-like, and diamond-like structures, respectively. The CuFe(BDC-NH2)D and CuFe(BDC-NH2)S were found to exhibit an improved PMS activation for Rhodamine B removal attaining levels around 92%. Their effective removal capability was investigated as a function of the pH, catalyst dosage, and the effect of the application of UV radiation. The best degradation system was photo-assisted activation of PMS when CuFe(BDC-NH2)D and CuFe(BDC-NH2)S were used. Under these conditions, the degradation of a mixture of antibiotic and anti-inflammatory drugs (sulfamethoxazole and antipyrine) was evaluated with the results revealing the total degradation of both drugs after 1 h. A higher antibacterial activity was attained with the system CuFe(BDC-NH2)R/PMS due to the high copper content with respect to the others.

Ultra-small Stokes shift induced thermal robust efficient blue-emitting alkaline phosphate phosphors for LWUV WLEDs

High power phosphor converted light emitting diodes (pc-LED) are thought to be the next generation technology for lighting and high-tech electronics applications. To achieve optimal luminous efficiency, maximal color gamut and stable color reproducibility, the discovery of high efficient phosphor materials with suitable excitation matching, narrow band emission and robust thermal stability is essential. Herein, we design and construct a new family of alkaline phosphate phosphors ANa3Mg7(PO4)6:Eu2+ (ANMP:Eu2+, A = K, Rb and Cs) with rigid diamond-like chain structure. The results indicates that ANMP:Eu2+(A = K, Rb and Cs) phosphors exhibit ultra-small Stokes shift and efficient blue emission (λmax = 444–465 nm) with high internal quantum efficiency (IQE = 83.2%, 90.6% and 93.4% for A = K, Rb and Cs), narrow full width at half maximum (FWHM∼50 nm) and low thermal quenching (87.5%, 96.5% and 84.2%@140 °C for A = K, Rb and Cs), which demonstrate to have higher colorful purity, wider color gamut and better wavelength applicability for using in long-wavelength near ultraviolet (LWUV) LEDs, compared with the traditional commercially available blue phosphor BaMgAl10O17:Eu2+ (BAM:Eu2+). The Eu2+ site preferences and thermal quenching mechanism are studied in detail. Moreover, the in situ temperature dependent Raman spectra and density function theory (DFT) are employed to get better comprehensions of the relationship between crystal-electronic structures and luminescent properties from experiment and calculation, which will provide a good guidance for develop new phosphors with high QE and excellent thermal stability. Finally, utilizing the title phosphors, white LED lamps are fabricated with high color rendering index and an appropriate correlated color temperature. Therefore, all the results demonstrate that the blue-emitting phosphor ANMP:Eu2+ (A = Cs, K, Rb) has great potential for applications in high power LWUV pumped pc-LEDs.