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Meeting the growing demand for robust, earth-abundant and noble-metal-free photocatalysts for practical hydrogen-evolution reaction systems is crucial. Herein, cation modified perovskite niobates, Na0.5Sr0.5M0.25Nb0.75O3 (M = Cr, Mn, Fe, Co), are synthesized using a simple heterovalent coupled substitution strategy via solid-state reactions. The Cr compound as a single semiconductor system exhibits a photocatalytic hydrogen evolution rate of 188 μmol h−1 g−1, which significantly surpasses the performance of many contemporary catalysts that rely on the use of noble metal cocatalysts. Apparent quantum efficiencies (AQEs) of Cr, Mn, Fe and Co containing compounds are 2.24, 0.55, 0.65 and 0.74%, respectively. The photophysical properties like tuned band gap, suitable energy level positioning, charge carrier density, photostability of the materials and charge transfer resistance that are responsible for efficient spatial charge separation and charge transfer dynamics impacting the hydrogen evolution are investigated. This paper discusses the role of cation modification and its effects on the photophysical properties and hydrogen evolution activity of the perovskite niobates under noble-metal free conditions. These nonprecious noble-metal-free perovskite niobates furnish a new perspective for the future design of photocatalysts for efficient photocatalytic hydrogen evolution. [ABSTRACT FROM AUTHOR]

In this paper, a NiAl-LDH with the characteristic structure of a hydrotalc-like compound was applied as a carrier in a two-step hydrothermal process, and a MnCdS/In2S3/NiAl-LDH composite material was successfully prepared by loading MnCdS and In2S3 on the flower spherical-like surface of NiAl-LDH. The combination of NiAl-LDH with In2S3 and MnCdS made the band gap smaller and the light absorption range larger, thus increasing the utilization rate of light. 50% MnCdS/In2S3/NiAl-LDH composites had the best photoinduced charge separation and highest surface enrichment of photogenerated electrons. In the degradation experiment of crystal violet (CV), 50% MnCdS/In2S3/NiAl-LDH composites showed superior photocatalytic degradation efficiency (>98.5%) under full spectrum light. Furthermore, the applicability and universality of photocatalysts were studied by observing the degradation of CV by MnCdS/In2S3/NiAl-LDH composites under different conditions. In addition, the composites showed excellent hydrogen production capacity in the photolysis of water, in which hydrogen production within 8 hours was about 7661.51 μmol g−1. By combining the results of active species capture experiments, density functional theory (DFT) calculations and photoelectrochemical experiments, the possible mechanism of double S-scheme heterojunction photocatalysis among NiAl-LDH, In2S3 and MnCdS was inferred, which is one of the main reasons for the enhancement of photocatalytic activity. [ABSTRACT FROM AUTHOR]

The document is a contents list for the journal "Dalton Transactions: An International Journal of Inorganic Chemistry." It includes the titles and authors of various articles published in the journal, covering topics such as the synthesis and reactivity of hydride complexes, sustainable copolymers, and the structure and behavior of various metal complexes. The journal is published by The Royal Society of Chemistry, a leading chemistry community. [Extracted from the article]

The widespread use of antibiotics leads to the pollution of the water environment. Photocatalytic technology is considered as an effective way of removing antibiotics from the water environment. In this paper, a semi-embedded CdS/tubular g-C3N4 (CdS/TCN) heterojunction photocatalyst was designed and prepared by hydrothermal, in situ oil bath and thermal polymerization methods. Then Ni nanoparticles were loaded onto the surface of CdS/TCN by an in situ photoreduction method to form high performance photocatalyst Ni–CdS/TCN. The degradation rate of tetracycline hydrochloride (TCH) by Ni–CdS/TCN-6 was about 1.9 times higher than that of bulk carbon nitride (BCN) under visible light irradiation for 30 min. The high specific surface area, the effective heterojunction and loaded Ni broaden the light absorption range, narrow the band gap and improve the photogenerated carrier separation efficiency and migration rate. Beyond that, loaded Ni also inhibits photocorrosion and improves the stability of the photocatalyst. The present work provides a new way for designing a semi-embedded heterojunction photocatalyst. [ABSTRACT FROM AUTHOR]

This paper reports on the photodegradation of the Rh 6G dye using a g-C3N4 (g-CN) nanosheet photocatalyst under UV light irradiation. The g-C3N4 nanosheets were synthesized using a simple pyrolysis method at 450 °C for 3 h at a heating rate of 2 °C min−1. Their structural phase, functional groups, surface area, optical properties, elemental composition, and morphology were investigated via XRD, BET, UV-vis, photoluminescence spectroscopy, X-ray photoelectron spectroscopy, energy dispersive spectroscopy, and SEM microscopy. The tri-s-triazine structure of g-C3N4 was confirmed and the crystal size was calculated to be 5 nm. g-C3N4 displayed a nanosheet morphology with a BET surface area of 8 m2 g−1. C–N stretching and s-triazine units were observed in the FTIR spectrum. The photoluminescence (PL) emission maximum at 432 nm provided band edge emission related to a band gap of 2.9 eV, and the PL lifetime was 7.6 ns, which is reasonably high for photocatalytic application. Through the C1s XPS spectrum, sp2-hybridized carbon linkages of N–C＝N in the aromatic skeleton rings, such as triazine or heptazine rings, of g-C3N4 were found. The photocatalytic characteristics of g-C3N4 were studied with the Rh-6G dye using UV light illumination. Initially, the Rh-6G dye concentration and catalyst (g-C3N4) loading were optimized for the best dye degradation at 0.01 mmol and 50 mg, respectively. The maximum efficiency of g-C3N4 was 99.6% degradation of the Rh-6G dye in 300 minutes. Lower charge-transfer resistance was found to be the reason for the enhanced photodegradation activity. The most dominant reactive species that participated in the light-activated reaction were superoxide radicals. The influence of pH on photodegradation was studied and the photocatalyst was found to perform better in an acidic pH range. In addition, g-C3N4 was structurally stable, highly recyclable, and, therefore, could be reused in many cycles of photocatalysis. [ABSTRACT FROM AUTHOR]

As a new generation of photoelectric materials, organic-inorganic halide perovskites have been widely used in photodetectors, solar cells and other fields, but most of the current mainstream applications are thin film materials. Compared with polycrystalline thin films, perovskite single crystals have fewer grain boundaries and relatively stable electron and hole transport, and are ideal materials for optoelectronic devices. To realize the controllable growth of CH3NH3PbBr3 (MAPbBr3) crystals, understand their growth mechanism, and reflect the inherent physical and chemical properties of the material, a new type of internal growth temperature control and external circulation cooling growth system was developed in this paper, which can accurately control the temperature change during crystal growth. The size of the grown MAPbBr3 single crystal reaches 62 × 58 × 23 mm³, which is the largest single crystal reported to date. The measured single crystal absorption cut-off edge, optical band gap, and carrier lifetime are superior to the traditional simple inverse temperature crystallization (ITC) method, which will help its deep applications in photovoltaics, optoelectronics, and X-ray imaging. [ABSTRACT FROM AUTHOR]

Phosphates, whose obvious disadvantage is the relatively small birefringence, can be overcome by the introduction of post-transition metal cations containing stereochemically active lone-pair electrons. In this paper, two new compounds were successfully explored in the A–Sb–P–O system, i.e. Cs2Sb3O(PO4)3 (CsSbPO) and (NH4)2Sb4O2(H2O)(PO4)2[PO3(OH)]2 (NH4SbPOH). Transmission spectra show that CsSbPO has a surprising transmission range with a UV cutoff edge of 213 nm. First-principles calculations show that both compounds have a wide band gap (5.02 eV for CsSbPO and 5.30 eV for NH4SbPOH) and enlarged birefringence (Δn = 0.034@1064 nm for CsSbPO and Δn = 0.045@1064 nm for NH4SbPOH). The results of real-space atom-cutting investigations show that the distorted [SbOx] polyhedra originating from the asymmetric lone pair electrons give the main contribution to the total birefringence and overcome the disadvantage of small birefringence of phosphates but maintain wide transition windows. [ABSTRACT FROM AUTHOR]

This paper reports three new crystallographically characterized europium complexes with composition as follows: [Eu(fod)3(L1)] (1), [Eu(fod)3(L2)] (2) and [Eu(fod)3(L3)] (3) {L1 = benzimidazole (bzi), L2 = 4,7-diphenyl-1,10-phenanthroline (bath), L3 = 2-(2-pyridyl) benzimidazole (py-im) and fod = anion of 6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octanedione (Hfod)}. The single crystal (SC) XRD analysis shows that complex 1 is seven-coordinated while complexes 2 and 3 are eight-coordinated with the geometrical structures of a mono-capped octahedron and a trigonal dodecahedron, respectively. The NMR spectra of the complexes validate the SC-XRD results in solution. The complexes are stable in solution as no dissociation of any ligand was observed in the NMR spectra of the complexes. The photophysical properties of the complexes in solution, solid state, and PMMA thin films were studied. The hypersensitive transition 5D0 → 7F2 dominates the emission spectra in all phases, showing the highly asymmetric environment around the Eu(III) ion. The bath ligand is found to be the best sensitizer of the Eu ion and hence complex 2 shows the strongest luminescence properties with the highest absolute quantum yield among the three complexes. The CIE coordinate analysis shows that pure red-luminescence is emitted by the Eu complexes in the solid state since the coordinates found in this phase are closer to the standard NTSC 1987 values. The optical band gaps were determined for the complexes and the observed values suggest that the complexes can have possible applications in the field of semiconductor materials. [ABSTRACT FROM AUTHOR]

Hetero[8]circulenes have been proposed as promising fluorescent emitters for organic light-emitting diodes and as emerging materials in the construction of organic solar cells. Among them, octathio[8]circulene (C16S8) and its derivative tetrathiotetraseleno[8]circulene (C16S4Se4) crystals have been highlighted as efficient charge transport materials in field-effect devices. Using density functional theory, we investigate in this paper the electronic and optical properties of the C16S8 and C16S4Se4 molecules and crystals in order to revise previously reported controversial experimental data and report highly reproducible new results. We find that formation of the crystals results in a significant band gap decrease (∼0.6–0.7 eV) caused by relatively strong intermolecular interactions. A partial replacement of S atoms with Se atoms also leads to a small band gap reduction. The C16S8 crystal demonstrates a band gap of 3.32 eV, while a band gap of 3.20 eV is found for C16S4Se4. Both C16S8 and C16S4Se4 compounds are optically transparent in the visible region, confirming the absence of red coloration reported previously in one of experimental papers. The C16S8 and C16S4Se4 crystals demonstrate anisotropic electronic, mechanical and optical properties. These findings might initiate future experimental studies of the red color origin for C16S8 and provide insight for the design and engineering of C16S8 and C16S4Se4 based charge transport and optical devices. [ABSTRACT FROM AUTHOR]

On account of the development of deep-ultraviolet (DUV) nonlinear optical (NLO) crystals, tetrahedron-based compounds have attracted more and more attention, due to their large band gap. Thus, it is urgent to study a lot of these crystals for conducting structural optimization to achieve a balance of optical properties. Thus, this paper designs and obtains the Li2NH4Rb(SO4)2 crystal, an alkali metal sulfate, which is composed of an optimized KBe2BO3F2-like structure and disordered Rb and [NH4] cations. It exhibits a strong second-harmonic generation (SHG) response of 2 × KH2PO4, a large band gap of 7.56 eV and a favorable growth habit to large crystals, simultaneously. Thus, the Li2NH4Rb(SO4)2 crystal is a typical tetrahedron-based DUV NLO example. The coordination of the optimized KBe2BO3F2-like structure and the disordered cations results in the strong SHG response. This structural design strategy will facilitate the exploration of novel DUV NLO crystals. [ABSTRACT FROM AUTHOR]

Copper sulfides have gained significant attention as alternative electrodes for rechargeable batteries. A simple and easily scalable synthetic pathway to access these materials is highly desirable. This paper describes the facile synthesis of metal-rich digenite Cu1.8S nanocrystals from a structurally characterized new single-source molecular precursor in various high boiling solvents of varied polarity. The as-prepared nanostructures were thoroughly characterized by PXRD, Raman spectroscopy, EDS, XPS, electron microscopy techniques and diffuse reflectance spectroscopy to understand the crystal structure, phase purity, elemental composition, morphology and band gap. It was found that the reaction solvent has a profound role on their crystallite size, morphology and band gap, however the crystal structure and phase purity remained unaffected. Pristine Cu1.8S nanostructures have been employed as an anode material in lithium-ion batteries (LIBs). The cell delivers a high initial charge capacity of ∼462 mA h g−1 and retains a capacity of 240 mA h g−1 even after 300 cycles at 0.1 A g−1. DFT calculations revealed that multi-size polyhedron layers in the direction perpendicular to the two Li movement channels aid in the sustainable uptake of Li atoms with controlled volume expansion. The structure-mediated flexibility of the metal-rich Cu1.8S lattice during lithiation permits high cyclability with reasonable retention of capacity. [ABSTRACT FROM AUTHOR]

Covalent organic frameworks (COFs) are efficient semiconductor materials with superior catalytic activity and adjustable band gaps for the efficient degradation of organic pollutants in water. However, the synthetic yield of COF is generally small and only exists in the laboratory stage. In this paper, we introduced an emulsifier-mediated strategy into the synthesis of a COF for the first time and synthesized a COF with higher crystallinity and a higher synthetic yield of 84.7%. The specific surface area of BJH was also increased from 388.7 m2 g−1 to 1678.5 m2 g−1 and the photocatalytic degradation efficacy of 10 ppm methylene blue was increased from 26% to 100% within 50 min. This work provides a promising strategy to achieve a COF with a higher surface area, synthetic yield and photocatalytic efficacy via the emulsifier-mediated strategy, which would promote the industrial and practical production of COFs. [ABSTRACT FROM AUTHOR]

In this paper, NiCo2S4 was coated on the surface of WS2 of a 1T/2H mixed phase by a two-step hydrothermal method to form an in situ core–shell structure. The unique S-scheme heterojunction of the NiCo2S4@WS2 core–shell composite photocatalyst improved the easy recombination of carriers caused by the narrow band gap of NiCo2S4 and WS2, and improved the photocatalytic hydrogen production performance. The loading ratio of NiCo2S4@WS2, the addition of Eosin Y, and the pH value of TEOA were optimized. Under the optimal conditions, the hydrogen production rate reached 5.814 mmol g−1 h−1, which is about 8.55 times and 3.35 times the hydrogen evolution rates of NiCo2S4 and WS2, respectively. The composite catalyst exhibits excellent charge separation efficiency in photoelectrochemistry, PL and BET tests, carrier transport rate and large specific surface area that can provide more active sites, which are the main factors for the improvement of the hydrogen evolution performance. This paper demonstrates new design strategies to drive efficient photocatalytic hydrogen production by building in situ core–shell structures and optimizing the carrier transport paths, which will yield new insights. [ABSTRACT FROM AUTHOR]

In this paper, a series of BN/NTCDA photocatalysts have been prepared using a simple calcination method and their photocatalytic performance under visible light irradiation is studied with tetracycline (TC) as the target pollutant. When the ratio of BN and NTCDA is 100 : 1 and the temperature is 350 °C, the sample (BN/NTCDA (100 : 1)) has the highest adsorption efficiency (28.65%) and photodegradation efficiency (51.54%) for TC. The characterization results of XRD, FTIR, XPS, TEM, and 1H NMR show that BN/NTCDA (100 : 1) is a BN-based photocatalytic material, which is likely formed through the reaction of the surface hydroxyl group of BN and the anhydride of NTCDA. The band gap of BN is about 4.11 eV, and the band gap of NTCDA is 2.67 eV. So, the electron is firstly excited from the VB of NTCDA to its CB, and then the electron in the VB of BN is excited into the empty VB of NTCDA, implying that TC is degraded by photoactive species (˙O2−, h+ and ˙OH) from the VB of BN and CB of NTCDA. The capture experiment of photoactive species suggests that ˙O2− makes the main contribution to TC photodegradation, followed by h+, ˙OH. After five recycle experiments, BN/NTCDA (100 : 1) still has 77.32% removal efficiency for TC. The removal efficiency (80.19%) of BN/NTCDA (100 : 1) is higher than that of TiO2 (75.63%) and g-C3N4 (24.44%). This work contributes to the development of novel metal-free-photocatalysts and the application of photocatalytic technology to the removal of antibiotics. [ABSTRACT FROM AUTHOR]

Biowaste-derived carbon quantum dots (CQDs) offer a wide range of applications, including bioimaging, drug degradation and manufacturing of sensors, photodetectors and photosensitisers. However, inaccurate measurements of their quantum confinement and valence/conduction band potentials complicate their application predictability. Herein, we report carbon dots synthesized hydrothermally (600 °C; 6 h) using sugarcane bagasse powder (SC-CQDs). These SC-CQDs were characterized through UV-visible, fluorescence, PXRD, XPS, DLS, FTIR, Raman, SEM, EDAX and TEM analyses. The obtained SC-CQDs resemble amorphous N-doped multilayer-nanographene-type spherical particles with a size of 9.09 nm and has a band gap of 2.46 eV (λabs: 298 nm) with –COOH/–OH functionalities. The quantum confinement and valence/conduction band potentials were estimated using Brus-Kayanuma quantum mechanical (BKQM) and virtual molecular dynamics (VMD) equations. These CQDs are potential candidates for sunlight-mediated methylene blue degradation in water within 36 min for up to four catalytic cycles. [ABSTRACT FROM AUTHOR]

For the development of Bi/Bi2O3@Al2O3 nanocomposites for wastewater treatment, corrosion resistance, and self-cleaning properties, it is imperative to carefully combine and analyze various elements for the optimization of catalyst performance. We aim to provide effective and long-term environmental remediation solutions. FTIR spectroscopy, XRD, SEM, EDS, TEM, UV-vis spectroscopy, PL, and TGA techniques were used to characterize the Bi/Bi2O3@Al2O3 nanocomposite. The nanocomposite displayed significant supercapacitance and self-cleaning properties. A composite of bismuth–aluminum oxides was used as a catalyst to facilitate the catalytic reduction of 4-nitrophenol (4-NP) dye in aqueous solutions, and excellent catalytic reduction results were obtained. The photocatalyst catalyzed the reduction of 4-NP to 99% with a rate constant of 2.592 × 10−2 (10−2 min−1) in a short period of 40 minutes under UV-visible irradiation. Photogenerated electrons migrate from Bi/Bi2O3@Al2O3 when exposed to visible light as a result of the significant band gap in the conduction band and the structure of the core electrostatic field within the p–n heterojunction. When exposed to visible light, the Bi/Bi2O3@Al2O3 nanocomposite exhibited more charge separation with excellent catalytic reduction efficiency. It represents an important development since it offers effective wastewater treatment remedies, energy storage, and self-cleaning properties. [ABSTRACT FROM AUTHOR]

Sulfatotungstates constitute a rather new host structure materials that may exhibit interesting optical properties. The compounds M2[W2O3(SO4)6], with M = Y, Eu, Tb, Lu, and Bi, were synthesised as phase pure materials under solvothermal conditions in oleum. They crystallise isotypic to each other in the monoclinic space group C2/c (no. 15) with Z = 4, determined by single-crystal X-ray diffraction. Their structures feature corner-connected sulfate and tungstate units, the latter showing a disorder of the tungstate cations with a thread-like arrangement along the b-axis. The metal cations M are eight-fold-coordinated and show typical red (M = Eu) or green (M = Tb) luminescence in fluorescence spectra due to their f–f transitions. The f–d transition of Tb3+ reveals rather weak coordination behaviour of the host structure. Thermal analysis showed relatively high temperature stabilities of the compounds, increasing as the ionic radii of the metal cations decrease. Additionally, the compounds were characterised by FT-IR and UV-vis measurements while using Tauc plots to determine their band gaps. The lone-pair activity of the bismuth compound was elucidated by geometrical calculations based on the structural data. [ABSTRACT FROM AUTHOR]

In this study, we utilized first-principles methods to delve into defect clusters within potassium dihydrogen phosphate (KDP) crystals, focusing on (MgK + VK) and (MgK + VH) configurations. We examined their stability, defect formation energy, lattice distortion, electronic structures, and optical properties in both paraelectric (PE-KDP) and ferroelectric (FE-KDP) phases. In the PE phase, compensation of was accomplished via the nearest neighbor. Conversely, in the FE phase, compensation of was achieved utilizing the next nearest neighbor. Notably, the Mg–O ionic bond displayed significant changes in bond length, with a maximum alteration of 60%, as neighboring oxygen atoms moved closer to the magnesium atom. Furthermore, both structures displayed a downward shift of the conduction band minimum (CBM), primarily due to contributions from Mg 3s and O 2p orbitals, resulting in a reduction in the band gap. By analyzing the photoluminescence process alongside electron–phonon coupling phenomena, absorption and emission spectra were obtained. In the absorption spectra, peaks for PE-KDP and FE-KDP were observed at 335 nm and 386 nm, respectively, consistent with experimental observations of absorption at 355 nm. Upon exposure to a 355 nm laser, local crystal absorption led to a progressive increase in temperature, consequently lowering the damage threshold. [ABSTRACT FROM AUTHOR]

Double helicenes, with their notable chirality and intriguing properties, have captivated the great interest of chemists. Comprehending the relationship between their structure and properties is fundamentally significant for enhancing performance and facilitating practical applications. In this study, we have explored the photophysical properties of a series of double helicenes, composed of two perylene diimides (PDIs) entwined via C–C single bonds, using density functional theory (DFT) calculations. These properties include electronic transition characteristics, absorption spectra, and second-order nonlinear optical (NLO) responses. The simulated electronic absorption spectra of the parent compound (compound 1) closely resemble the experimental results. Compound 1 also exhibits an intrinsic second-order NLO response. Compounds 2–7, designed by substituting the terminal CH3 groups in compound 1 with electron acceptors (NO2, 7,7,8,8-tetracyanoquinodimethane (TCNQ)), electron donors (NH2, tetrathiafulvalene (TTF)), and their combinations, demonstrate tunable HOMO/LUMO distributions, band gaps, absorption intensities, and electron transition properties. Notably, the maximum βHRS value reaches 8.71 × 10−30 esu, approximately 95 times greater than that of the organic molecule urea. Our findings provide insights for the development of double helicenes with PDI subunits. [ABSTRACT FROM AUTHOR]

A comprehensive DFT investigation has been presented to predict how a carboxylate-rich macrocycle would affect the reactivity of a non-heme Fe(IV)O complex towards C–H activation. The popular non-heme iron oxo complex [FeIV(O)(N4Py)]2+, (N4Py = N,N-(bis(2-pyridyl)methyl)N-bis(2-pyridylmethyl)amine) (1), has been selected here as the primary compound. It is transformed to the compound [FeIV(O)(nBu-P2DA)], where nBu-P2DA = N-(1′,1′-bis(2-pyridyl)pentyl)iminodiacetate (2) after the replacement of two pyridine donors of N4Py with carboxylate groups. Two other complexes, namely 3 and 4, have been predicted sequentially substituting nitrogen with the carboxylate groups. Ethylbenzene and dihydrotoluene were chosen as substrates. In terms of C–H activation reactivity, an interesting pattern emerges: as the carboxylate group becomes more equatorially enriched, the reactivity increases, following the trend 1 < 2 < 3 < 4. This also aligns with available experimental reports related to complexes 1 and 2. Fe(IV)O complexes exhibit two-state reactivity (triplet and quintet), whereas the quintet state is more favourable due to the stabilization of the transition states through exchange interactions involving a greater number of unpaired electrons. A detailed analysis of the factors influencing reactivity has been performed, including distortion energy (which decreases for the transition state with the addition of carboxylate groups), the triplet–quintet oxidant energy gap (which consistently decreases as carboxylate group enrichment increases), steric factors, and quantum mechanical tunneling. This investigation provides a detailed explanation of the observed outcomes and predicts the higher reactivity of carboxylate-enriched Fe(IV)O complexes. After potential experimental verification, this could lead to the development of new, optimal catalysts for C–H activation. [ABSTRACT FROM AUTHOR]

Metal chalcogenides, as a new class of semiconductor materials, have a broad range of applications in synthetic chemistry due to their rich structures and excellent properties. We have synthesized two selenoantimonates A4Zn2Sb2Se7 [A = Rb(1), Cs(2)] under solvothermal conditions in the visible region using a band gap optimization strategy with alkali metals as structure-directing agents. Compounds 1 and 2 have a two-dimensional layered structure consisting of charge-balanced Rb+(1) or Cs+ (2) cations and [Zn2Sb2Se7]4- anions with novel 20-membered rings (20-MR) [Zn6Sb4Se10] with an aperture of 5.6949 × 13.7741 Ų formed in the middle. Furthermore, we have investigated the crystal structure, band gap, photoelectronic properties, and energy band structure. [ABSTRACT FROM AUTHOR]

In this manuscript, a simple one-pot heat-up method has been used to prepare multi-component copper-tin-sulfur nanomaterials, including binary Cu1.94S, ternary Cu4SnS4, and Cu1.94S/Cu4SnS4 nanocrystals by varying the reaction temperature, reaction time, and the type of copper source. Post-synthetic ligand exchange (LE) has further been introduced to replace the long-chain ligands originating from 1-dodecanethiol. It has been found that the LE process not only changes the surface ligands but also significantly affects the crystal structure and optical properties of nanocrystals. After LE, the crystal structures of Cu1.94S and Cu4SnS4 transformed to Cu7S4 and Cu3SnS4, respectively, with the Cu1.94S/Cu4SnS4 nanocrystals showing the same trend. This phenomenon could be ascribed to the loss of Cu+ originating from the strong complexation of Cu+ and ammonia with the formation of [Cu(NH3)n]2+ ions under aerobic conditions. Proton nuclear magnetic resonance (1H NMR) has been used to characterize the ligands on the surface before and after LE, which further demonstrated that the -SH was replaced during LE. Meanwhile, the band gaps of the obtained nanocrystals after LE show an obvious shift in the near-infrared region due to the evolution of crystal structures. This study will provide useful guidance for the LE of nanocrystals and the application of copper-based sulfide nanomaterials in optoelectronics and other fields. [ABSTRACT FROM AUTHOR]

Ni3S4 and Ni3S4:Co nanoparticles are successfully synthesized by a diffusion control synergistic trapped dopant method. The photoluminescence peak of Ni3S4 can be enhanced clearly owing to Co atom doping, which implies that the doped Co atoms can effectively adjust the fluorescence performance of Ni3S4 nanoparticles. Moreover, the photoluminescence (PL) peak intensity of Ni3S4:Co nanoparticles increases first and then decreases with the increase of Co atom doping content. The lifetime values of Ni3S4:Co are significantly shorter than those of pure Ni3S4, measuring less than 1 ns. The presence of Co atom doping can reduce the band gap of Ni3S4 and improve the electrical conductivity of the materials, thus favoring electron transition. Additionally, the enhanced orbit coupling effect of S, Ni and Co atoms is also beneficial to improve the luminescence of Ni3S4:Co materials. [ABSTRACT FROM AUTHOR]

We have investigated the electronic properties of lithium, sodium, and potassium doped endohedrally on C20 fullerenes, through DFT calculations. The dipolar moment, average binding energies, cohesion energy, ‖HOMO–LUMO‖ energy gaps and NBO population analysis are expressed as functions of Li amount. The electrons transferred by lithium are distributed on the surface of the C20. The excess charge induces a decrease in the gap value, which allows the structure to behave like a semiconductor material. The obtained results indicate that the C20 fullerenes are highly efficient in adsorbing Li atoms, as the retention capacity of Li@C20, Na@C20, and K@C20 exceeds 1458.9, 1146.3, and 907.4 mA h g−1, respectively. The Li@C20 complex provides a maximum voltage of 1.1 V. The insertion of Na and K increases the adsorption energy, so the voltage also increases to 2.2 and 2.4 V. This makes them an alternative for energy storage. [ABSTRACT FROM AUTHOR]

The ternary ZnIn2S4 has recently gained significant attention due to its potential applications in various optoelectronics and photocatalysis sectors. In the current study, ZnIn2S4 nanoparticles were prepared using a simple microwave-assisted synthesis method with different irradiation powers varying from 180 W--720 W. Structural analysis confirmed their polycrystalline nature with the appearance of ZnIn2S4 and In2S3 phases. The variation in diffraction pattern intensity and Raman vibrational bands with irradiation power indicates structural rearrangements induced with power variation. Morphological studies confirmed the formation of agglomerate nanoparticles with size variation as induced by different microwave powers. Broad absorption across the visible and near-infrared regions and the increased band gap enhance their photocatalytic and sensing applications. An increased irradiation power in the ZnIn2S4 lattice reduced intermediate levels within the band gap, altering the optical responsiveness. The blue shift in absorption edges with microwave power increased the optical band gap by reducing disorder and defects. The refractive indices were estimated using different theoretical models and reduced with an increase in the band gap. Thermal analysis revealed endothermic peaks. These ZnIn2S4 nanoparticles displayed an enhanced photocurrent under white light, increasing tenfold with microwave power. The greater powered ZIS (ZIS-720 W) nanomaterial showed the best photoresponse and is well suited for optoelectronic application. All of their optical and electrical properties make them suitable for various optoelectronic devices, particularly in detection applications. [ABSTRACT FROM AUTHOR]

Significant global concerns about the environment include the removal of various organic dye contaminants and the detection of toxic nitrite (NO2−). Herein, we developed a novel composite that combines an inorganic perovskite-based alkaline earth stannate (CaSnO3) with aurivillius oxide (Bi2WO6). These components were synthesized by combustion and hydrothermal methods, respectively. The composite was designed for the photocatalytic degradation of methylene blue (MB) and electrochemical sensing of nitrite. The prepared composite was systematically characterized using various analytical techniques to verify its elemental composition and morphology and to determine the particle size and band gap. CaSnO3/Bi2WO6 exhibited a remarkable 92.5% degradation of the carcinogenic MB dye under UV light over approximately 180 minutes. Importantly, it was observed that the designed nanocomposite did not exhibit photo-corrosion properties as the degradation of MB occurred even at pH 11. Furthermore, the CaSnO3/Bi2WO6-modified glassy carbon electrode (GCE) demonstrated excellent electrocatalytic activity, with an obtained limit of detection (LOD) of 0.9 μM. In this work, the CaSnO3/Bi2WO6 nanocomposite shows promising potential for efficient photocatalytic dye degradation and electrochemical sensing of nitrite, with the added advantage of avoiding photo-corrosion even under alkaline conditions. [ABSTRACT FROM AUTHOR]

Antimony/bismuth-based organic–inorganic hybrid halide perovskite-like compounds have generated enormous research interest due to their excellent optical properties. Exploration of new compounds and understanding of their structural stability and optoelectronic properties is of utmost importance for practical applications of these materials. We report two new 0D perovskite-like compounds and their solid solution, (C3H7NH3)4Bi1−xSbxI9, having propyl amine as the spacer cation and iodine as the halide ion. All compounds crystallized in the space group C2/m at room temperature and undergo a phase transition from C2/m to P21/c at low temperature (90 K) as observed from the single-crystal study. A low-temperature (250 K, 180 K, 150 K and 90 K) single-crystal study shows that the (PA)4BiI9 compound retains the monoclinic space group C2/m until 150 K and undergoes a phase transition to the P21/c space group at 90 K. Further, it is observed that ordering, rearrangement and relaxation of the long-chain propyl amine group are primarily responsible for the structural transition. The structure contains [(Bi/Sb)I6]3− polyhedra along with linear I3− units, giving rise to the formula of (PA)3(Bi/Sb)I6·(PA)I3. The I3− units interact poorly while the [MI6]3− (M = Bi, Sb) octahedral units interact significantly with spacer cations via the H-bond, resulting in more distortion in these octahedral units. Theoretical calculations revealed that iodide ions have dual roles and contribute largely to both the valence band maxima and conduction band minima in these compounds. From both experimental and theoretical calculations, it is observed that the pristine compounds are of the indirect band gap-type and Sb substitution in (PA)4Bi1−xSbxI9 led to a gradual decrease in the band gap. [ABSTRACT FROM AUTHOR]

Multinuclear (di/tri) copper(II) complexes bridged through hydroxyl groups are very interesting coordination complexes owing to their potential applications in various fields. In this work, three novel dinuclear (μ-hydroxo)-bridged copper(II) complexes in the crystal form, namely, [Cu2(3,5-DIFLB)2(H2tea)2](H2O) (1), [Cu2(4-ClB)2(H2tea)2](H2O) (2), and [Cu2(4-ETHB)2(H2tea)2](H2O)2 (3) (where DIFLB = difluorobenzoate, CLB = chlorobenzoate, ETHB = ethoxybenzoate, and H3tea = triethanolamine), were isolated at room temperature using methanol and water in a 4 : 1 v/v ratio as a solvent. Furthermore, all three complexes (1–3) were characterised using spectroscopic (UV-vis, DRS, and FT-IR), electrochemical (CV) and single-crystal X-ray diffraction techniques. Structural insights gained by packing analysis revealed the role of steric constraints of substituents and various non-covalent interactions in lattice stabilization, which were indeed supported by theoretical and molecular electrostatic potential illustrations. Hirshfeld surface analysis provided quantitative verification about various non-covalent interactions (interatomic contacts) involved in the packing of molecules. Interestingly, as a potential application, complexes 1–3 all exhibited remarkable visible light-mediated photo-Fenton degradation of approximately 98% for 50 ppm concentration of organic dyes (fuchsin basic (FB) and methyl orange (MO)) in 90 minutes with the optimized conditions of 1 mg mL−1 of dye solution. In all the cases, dye degradation by these materials was ascribed to the symbiotic relations among the molecular structures of complexes 1–3, which were endowed with various electron-withdrawing and electron-releasing substituents and ionic strength, with respect to the structure, shape and interacting patterns of dye molecules. The adsorption mechanism indicates that various weak interactions between the donor and acceptor groups of complexes and dyes, such as electrostatic, hydrogen bonding, and direct coordination to metal sites, play a crucial role, which is confirmed by molecular dynamics (MD) simulations. Theoretical studies by DFT-based descriptors, molecular electrostatic potentials, and band gaps provided deep insights into various electronic and reactivity parameters. For subsequent processes of dye degradation, complexes 1–3 were stable and recoverable. The successful integration of experimental and theoretical approaches sheds light on copper-based dinuclear stable coordination complexes, showcasing a significant step towards the development of novel heterogeneous photo-Fenton catalysts. [ABSTRACT FROM AUTHOR]

The change in local, semi-local and peripheral aromaticity of coronene upon gradual replacement of its peripheral CC bonds with BN bonds, starting from the C3h symmetrical 3-BN derivative, was followed by calculating HOMA, PDI, FLU, EDDB and NICS-xy scans. They were calculated using B3LYP-D3(BJ), M06-2X and ωB97XD functionals, whose results agreed very well. It was found that introduction of BN units instead of CC units can, more or less, isolate aromatic carbocyclic subunits and increase peripheral electron delocalization. These subunits dominate the frontier orbital shapes and energy gap, thus enabling their modulation by applying BN/CC isosterism. [ABSTRACT FROM AUTHOR]

Four new POM-based coordination complexes [Cu(TPP)2(CH3CN)2]2{[Cu(TPP)2]2(β-Mo8O26)}·2CH3CN (1) (TPP = triphenylphosphine), {[Ag(TPP)]2·[Ag(TPP)2]2·(β-Mo8O26)}·6DMF (2), {[Cu2(DPPM)2(CH3CN)]2(β-Mo8O26)}·2CH3CN·2DCM (3) (DPPM = bis(diphenylphosphino)methane), and {[Ag2(DPPM)2·(CH3CN)]2(β-Mo8O26)}·2CH3CN·2DCM (4) were prepared through the self-assembly of α-octamolybdates and the corresponding Cu/Ag phosphine building blocks. Single crystal X-ray diffraction reveals that compound 1 consists of two cations of [Cu(TPP)2(CH3CN)2]+ and one anion of {[Cu(TPP)2]2(β-Mo8O26)}2−; the anion of {[Cu(TPP)2]2(β-Mo8O26)}2− can be viewed in such a way that the central cluster of β-Mo8O26 are coordinated with two Cu(TPP)2 units via terminal oxygen atoms to form a linear trimer; compound 2 is a neutral cross-like pentamer which is made up of the central β-Mo8O26 coordinated with two equatorial Ag(TPP)2 units and two Ag(TPP) units above and below the β-Mo8O26 cluster via the terminal oxygen atoms; compounds 3 and 4 can be viewed as a trimer consisting of two binuclear metal clusters of {[Cu2(DPPM)2(CH3CN)]2}2+ or {[Ag2(DPPM)2(CH3CN)]2}2+ bridged by one β-Mo8O26 cluster via terminal oxygen atoms. Their structures are further evidenced by FT-IR and PXRD. TGA study indicates that the skeleton of compounds 1–4 is stable up to 250–290 °C and then a rapid weight loss followed. Their band gaps can be calculated (Eg value: 2.27 eV for 1, 3.14 eV for 2, 2.66 eV for 3, and 3.16 eV for 4) using the Tauc's method according to their solid state UV diffuse reflection spectra. Upon irradiation at 211 nm, compounds 1–4 exhibit a series of successive emissions around 360 nm, 380 nm and 400 nm, which demonstrate a similar solid state emission compared to their corresponding Cu/Ag phosphine building blocks. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) semiconductors with suitable band gaps, high carrier mobility, and environmental stability are crucial for applications in the next generation of electronics and optoelectronics. However, current candidate materials each have one or more issues. In this work, two novel C3N2 monolayers, P-C3N2 and I-C3N2 are proposed by first-principles calculations. Both structures have demonstrated excellent dynamical and mechanical stability, with thermal stability approaching 3000 K. Importantly, P-C3N2 shows a distinct advantage in formation energy compared to currently synthesized 2D carbon nitride materials, indicating its potential for experimental synthesis. Electronic structure calculations reveal that both P-C3N2 and I-C3N2 are intrinsic semiconductors with moderate band gaps of 2.19 and 1.81 eV, respectively. Additionally, both C3N2 monolayers display high absorption coefficients up to 105 cm−1, with P-C3N2 showing significant absorption capabilities in the visible light region. Remarkably, P-C3N2 possesses an ultra-high carrier mobility of up to 104 cm2 V−1 s−1. These findings provide theoretical insights and candidates for future applications in the electronics and optoelectronics fields. [ABSTRACT FROM AUTHOR]

The pursuit of developing highly potent and environmentally friendly photocatalysts for water dissociation is crucial for the advancement and storage of unlimited solar energy, although it remains a massive challenge. Herein, we conducted a screening process for the photocatalytic water splitting capabilities of a multitude of members from the extensive MA2N4 family. Using first-principles calculations, we found MoSi2N4, WSi2N4 and WGe2N4 structures with excellent potential for photocatalytic applications. To be specific, these members possess semiconductor characteristics, featuring suitable band gap structures and pronounced optical absorption capabilities in the UV-visible light spectrum. Our findings suggest that with nitrogen vacancies present on the surface, MoSi2N4, WSi2N4, and WGe2N4 all demonstrate near-zero Gibbs free energy in driving the hydrogen evolution reaction. Simultaneously, MoSi2N4, WSi2N4, and WGe2N4 can spontaneously catalyze the overall water splitting reaction under light illumination at pH values of 4, 12, and 8, respectively. This investigation provides fresh perspectives in terms of designing highly efficient photocatalysts. [ABSTRACT FROM AUTHOR]

Element doping and construction of heterojunction composites are the most common ways to enhance g-C3N4, which are very attractive in achieving high photocatalytic activity. In this study, 2D nanosheet structured BCN was obtained by doping B atoms with graphite carbon nitride. Subsequently, Ti MOFs were loaded on BCN to obtain a Z-scheme heterojunction composite TBCN through calcination. Under simulated sunlight, the photocatalytic hydrogen production rate of the TBCN heterostructure was 1242 μmol h−1 g−1, which was 2.2 times higher than that of BCN and 9.34 times higher than that of bulk graphite carbon nitride (GCN). Experimental results showed that the construction of a Z-scheme heterojunction composite (TBCN) could effectively adjust the material band gap position, expand the light absorption range, enhance electron transfer and inhibit electron–hole recombination, which are crucial for efficient photocatalysis. This study not only provides a strategy for constructing heterojunction composites in the field of g-C3N4 photocatalytic hydrogen evolution, but also deeply analyzes the electron migration direction and the reasons for enhancing carrier separation in the Z-type heterojunction scheme, thus providing potential guidance for future research. [ABSTRACT FROM AUTHOR]

Cyanurate or isocyanurate compounds containing plane π-conjugated groups usually have giant optical anisotropy, which are promising candidates for optoelectronic functional materials. In this work, a new alkali-metal isocyanurate was successfully synthesized by a hydrothermal method, namely Cs3(H2C3N3O3)3(H3C3N3O3)·3H2O, belonging to the triclinic crystal and P1¯ space group. The compound has two-dimensional layers constructed with (H2C3N3O3)− and (H3C3N3O3) six-membered rings extending along the ab plane. The characterization results show that it exhibits a wide band gap (5.03 eV) and a large birefringence (0.23 at 1064 nm). In addition, in order to evaluate the relationship between the crystal structure and its optical properties, the first-principles calculation was also carried out. This work provided a possible candidate for anisotropic optical crystals applied in the ultraviolet region. [ABSTRACT FROM AUTHOR]

A novel CdS@TiO2@C/Ti3C2 composite as a high-efficiency photocatalyst for the degradation of tetracycline hydrochloride (TC-HCl) was fabricated by in situ oxidizing two-dimensional (2D) layered transition metal Ti3C2 MXene and subsequently compounding with CdS nanoparticles (NPs) via a two-step hydrothermal method. Benefitting from the in situ oxidation of Ti3C2 MXene, the derived TiO2@C/Ti3C2 composites possess excellent interface contact and uniform morphology distribution. Furthermore, the in situ grown TiO2 displays a nanosheet (NS) structure with high-energy (001) facets, which could bring about unique surface heterojunctions between the (101) and (001) facets of the TiO2 NSs. On the above basis, CdS NPs are introduced to effectively improve the light-harvesting ability in the visible region due to the narrow band gap and enlarged surface area. Meanwhile, the separation and transfer efficiencies of photo-generated carriers are significantly enhanced by the synergistic effect of the C/Ti3C2 matrix, surface heterojunctions of the TiO2 NSs and heterojunctions of CdS/TiO2. Therefore, the CdS@TiO2@C/Ti3C2 composites display remarkably enhanced photocatalytic ability for TC-HCl degradation under the irradiation of visible light, and the CdS@TiO2@C/Ti3C2-2 sample exhibits optimal photodegradation efficiency with a value of 85% within 60 min, which is 8.5 times higher than that of the TiO2@C/Ti3C2 sample. Additionally, the corresponding improved mechanism is also deeply discussed in the present paper. [ABSTRACT FROM AUTHOR]

The development of stable and durable oil/water separation materials with photocatalytic activity holds great significance for the purification of complex oily wastewater containing refractory organic pollutants. Herein, a multifunctional Ag@Cu2O decorated copper mesh was designed and prepared via a two-step hydrothermal method. The material possesses outstanding superwettability, photocatalytic activity, and antibacterial properties towards Escherichia coli and Staphylococcus aureus. The mesh demonstrates remarkable and durable superhydrophilic properties while maintaining underwater superoleophobic characteristics, enabling excellent separation efficiency and high permeability flux involving various oil/water mixtures in gravity-driven separation processes. Under visible light, the Ag@Cu2O anchored mesh serves as an effective photocatalyst in the removal of dyes and tetracycline antibiotics from aqueous solution. The catalyst shows high stability and reusability and exhibits high performance after 5 cycles of photocatalytic tests. Density functional theory calculations reveal that the improved photocatalytic performance is attributed to the narrowed indirect band gap after Ag anchoring. The silver atoms induce the shifting up of the energy level of the Cu 3d orbital, enhancing the photocatalytic activity of Cu2O. The outstanding performance of the Ag@Cu2O anchored mesh endows this material with great application potential in the removal of refractory pollutants from oily wastewater. [ABSTRACT FROM AUTHOR]

This study presents evidence that lead metavanadate, PbV2O6, is a material with zero-linear compressibility, which maintains its crystal size in one crystallographic direction even under external pressures of up to 20 GPa. The orthorhombic polymorph of PbV2O6 (space group Pnma) was studied up to 20 GPa using synchrotron powder X-ray diffraction, Raman spectroscopy, and density-functional theory simulations to investigate its structural and vibrational evolution under compression. Up to this pressure we find no evidence of any structural phase transitions by any diagnostic technique, however, a progressive transformation of the coordination polyhedron of vanadium atoms is revealed which results in the zero-linear compressibility. High-pressure Raman experiments enabled the identification and symmetry assignation of all 54 zone-centre Raman-active modes as well as the calculation of their respective pressure coefficients. Three independent high-pressure powder X-ray diffraction experiments were performed using different pressure-transmitting media (Ne, 4 : 1 methanol–ethanol mixture, and silicone oil). The results show a high anisotropic behaviour in the linear compressibility of the crystallographic axes. The PbV2O6 bulk modulus of 86.1(9) GPa was determined using a third-order Birch-Murnaghan equation of state. The experimental results are supported by ab initio density-functional theory calculations, which provide vibrational patterns, unit-cell parameters, and atomic positions. These calculations also reveal that, unlike MgV2O6 and ZnV2O6, the band gap of PbV2O6 closes with pressure at a rate of −54 meV GPa−1 due to the contribution of the Pb 6s orbital to the top of the valence band. [ABSTRACT FROM AUTHOR]

Bi5O7I doped with Zn2+ (Zn2+/Bi5O7I) was prepared using a precipitation calcination method. Its photocatalytic activity was improved by adjusting the band gap of Bi5O7I, and its photocatalytic performance was evaluated by degrading RhB. The experimental results showed that Zn2+/Bi5O7I-8 had the highest photodegradation efficiency, and the degradation rate for RhB after exposure to light for 30 minutes was 91% and reached 100% in 60 minutes. The degradation rate constant k of Zn2+/Bi5O7I-8 reached 0.10813 min−1, which is 13 times more than that of Bi5O7I. As a result of Zn2+ being added into Bi5O7I, the band gap of Zn2+/Bi5O7I became narrower than that of Bi5O7I, and the photogenerated electrons and holes were successfully prevented from recombining; therefore, the photocatalytic activity of Zn2+/Bi5O7I was higher than that of Bi5O7I. After four rounds of photocatalytic experiments, the photocatalytic efficiency of Zn2+/Bi5O7I-8 remained high. The composition and microstructure of the materials were characterized using XRD, FTIR, XPS, SEM, and TEM. The optical properties and degradation mechanism of the material were investigated using DRS, PL, photocurrent response, and active substance capture experiments. A suggested mechanism for the photocatalytic degradation of RhB is presented. [ABSTRACT FROM AUTHOR]

Silver indium selenide (AgInSe2) has been proposed as an efficient absorber material for sustainable solar cells. Phase pure preparation of this exotic material in the nano regime is highly desirable. This report describes the design and synthesis of a new heterobimetallic complex [(Ph3P)2Ag(μ-SeCH2Ph)2In(SeCH2Ph)2] along with its structural characterization. This complex acts as an air enduring, normal temperature and pressure (NTP) stable versatile single source precursor for synthesizing bulk, nanocrystalline and thin film of AgInSe2. The crystal structure, phase purity, morphology, elemental composition and band gap of the synthesized materials were determined from powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS) and diffuse reflectance spectroscopy (DRS-UV), respectively. The band gap of the nanocrystalline AgInSe2 lies in the range suitable for solar cell applications. A prototype photoelectrochemical cell fabricated with the pristine AgInSe2 nanoparticles exhibits high photoresponsivity, which makes them a suitable candidate for clean energy applications. [ABSTRACT FROM AUTHOR]

Four new donor–acceptor conjugated polymers based on the acceptor block 8,10-bis(2-octyldodecyl)-8H-dithieno[3′,2′:5,6;2′′,3′′:7,8]naphtho[2,3-d]imidazole-9(10H)-one and various donor moieties were synthesized. Binary and ternary composites comprising new polymers, PC71BM fullerene and non-fullerene acceptors based on indacenodithiophene, were developed. The mobility of electrons and holes in thin films of the ternary composites is balanced in contrast to that in binary composite films. This is explained by less aggregation in the ternary composite films and good matching of the frontier orbital energy levels of the composite components. [ABSTRACT FROM AUTHOR]

Eight new solvates of 1,1′-(1,4-phenylenebis(methylene))bis(1-pyridinium) hybrid halobismuthates were obtained from dimethyl sulfoxide (DMSO) and dimethylformamide (DMF) solutions and structurally characterized. The thermal stability of the solvates was studied using TGA/DSC methods, and the appropriate conditions for the solvent molecule loss were defined. As a result, five new hybrid halobismuthates were prepared by the thermal decomposition of the obtained solvates. Based on the synchrotron powder X-ray diffraction data, the structure of the anionic part of the crystal products produced by the thermal decomposition of solvates was determined. The optical band gap values were defined for all the prepared products. The proposed method for obtaining new hybrid halobismuthates is prospective for the synthesis of compounds, which cannot be prepared from solutions. [ABSTRACT FROM AUTHOR]

The results of quantum chemical modeling of the structure and electronic properties of tellurium nanorods using two different approaches to describing the symmetry of these objects are presented. The first one is based on the consideration of tellurium nanorods within the framework of subgroups of the P3121 space group of a bulk tellurium crystal (crystallographic rod groups L3121 and L31), which specify the order of the helical axis strictly equal to 3. The second one considers nanorods within the framework of the line group theory, which allows for a continuous change in the order of the helical axis for 1D objects and by this way to discuss the effects of the nanorod torsion. It is shown that in the absence of symmetry restrictions, the order of the helical axis of tellurium nanorods is greater than the crystallographic value 3, but tends to it with increasing of nanorod thickness. Therefore, the corresponding rod groups should be considered only as groups to which the true line group symmetry of the nanorods asymptotically tends as their thickness increases. For nanorods obtained experimentally, the difference between the true and crystallographic helical axis orders is so small that it is practically invisible at the nanometer level, but manifests itself at the mesoscale, leading to a visually observable helical twist of tellurium nanorods (see A. Londoño-Calderon et al. Nanoscale, 2021, 13, 9606). The dependences of the electronic band gap of nanorods on torsion are presented. Nanorod of a certain thickness has its own features of the electronic structure, which can be explained by the evolution of the topology of electronic bands in the helical Brillouin zone. [ABSTRACT FROM AUTHOR]

CuGaSe2, a ternary chalcopyrite, has recently garnered attention due to its potential in various optoelectronic and photonic devices. In this current study, 2D CuGaSe2 hexagonal nanosheets were synthesized using a simple microwave-assisted method with varying irradiation times from 3 min to 20 min. The variation in microwave irradiation confirmed its polycrystalline nature, revealing multiple binary phases of CuSe, Cu2Se, and Ga2Se3 with differing intensities. Changes in the diffraction pattern along with Raman vibrational band intensities indicate structural rearrangements within the system over time variation. Suitable 2D hexagonal nanosheets were observed from morphological studies with slight variations in the sheet thickness. Increasing irradiation time led to the introduction of intermediate levels within the band gap, which red-shifted the optical absorption edge. Such variations over time tend to reduce the optical band gap, introducing more disorder and defects inside the system. Broad reflectance across the visible and NIR spectrum and a reduced band gap make it promising for solar cell applications. The elemental composition and corresponding oxidation state have been confirmed by using different surface chemical analyses. The photocurrent response exhibited an ohmic nature, with slight improvement with irradiation time. The photo-resistance decreased with longer irradiation, possibly due to an increase in acceptor state concentration, boosting current density and reducing resistance at room temperature. This behavior is advantageous for photoresponse applications. [ABSTRACT FROM AUTHOR]

Inorganic–organic hybrid semiconductors based on copper(I) halide are intriguing luminescent materials possessing great prospects as rare-earth elements (REEs) free phosphors for use in solid-state lighting (SSL). However, it is still a great challenge to develop such hybrid semiconducting materials with high energy blue light emission and good thermal stability simultaneously. Here, we have synthesized a brand new, one-dimensional (1D) organic–inorganic semiconductor CuI-Pytz (Pytz = 4-(pyrid-2-yl)-1,2,4-triazole) using a solvent diffusion method, for which the structure was determined by single crystal X-ray diffraction (SCXRD) and shows great thermal stability and decomposition temperature up to 220 °C. At room temperature, this indirect band gap hybrid semiconductor shows a blue emission centered at 464 nm which was nearing deep blue light (<460 nm) with a band gap energy of 2.70 eV. In addition, we developed a simple method for large-scale synthesis of the microcrystal, which significantly enhances the possibility of widespread applications for CuI-Pytz. Both density functional theory calculations and experimental studies reveal that the blue light emission originates from the combination of metal-to-ligand charge transfer (MLCT) and halide-to-ligand charge transfer (XLCT). The good thermal stability and high energy blue light emission make this low-cost and easily available copper(I) halide hybrid semiconductor a potential candidate for use as rare-earth free phosphors. [ABSTRACT FROM AUTHOR]

Silver chalcogenide quantum dots (QDs) are potential nanosensors for biological and environmental applications. These QDs present low toxicity and their narrow band gap makes them promising as near-infrared (NIR) photoluminescence (PL) probes, exhibiting images with higher penetrability. In addition, hydrophilicity is essential for applications in biological systems as well as detection in aqueous media. Using the same methodology, variations in synthesis conditions can alter the efficiency and performance of their intrinsic properties. Most studies seek the best conditions for each experimental variable in a univariate manner; however, multivariate strategies are a faster and more economical way to achieve this goal. Thus, in this work, we utilized chemometric approaches to enhance the NIR-II PL properties of Ag2Se QDs stabilized with 3-mercaptopropionic acid (MPA). Three experimental designs were used, totaling 58 syntheses, showing that the Ag2Se–MPA QDs, obtained under the conditions of [Ag+] of 2.5 mmol L−1, Ag : Se molar ratio of 8 : 1, MPA : Ag molar ratio of 6 : 1, heating at 70 °C, pH 10, and 180 min, presented the best emission profile with a maximum at 1070 nm and a FWHM of approximately 140 nm. The nanocrystals presented an average diameter of 6 nm and the orthorhombic crystalline phase. Preliminary surface-enhanced infrared absorption (SEIRA) spectroscopy assays were carried out for the detection of methyl violet 2B (MV) dye using these QDs. The enhancement factor obtained was higher than 3.5, which is comparable to those observed for other systems, namely Ag2Se-MSA QDs. These results showed the potential of the Ag2Se–MPA QDs for (bio)sensing applications. [ABSTRACT FROM AUTHOR]

A unique series of compounds was prepared from glutaric acid and various 2-amino thiazoles via a simple yet efficient synthetic method at ambient temperature. The N-(thiazol-2-yl)piperidine-2,6-dione derivatives were synthesized and characterized using multiple physicochemical techniques, X-ray crystallography, and SHG analysis. 2 out of the 5 newly synthesized compounds displayed strong nonlinear optical (NLO) properties. All five compounds were studied computationally, and UV spectroscopy was used to confirm the second harmonic generation (SHG) phenomenon. It was found that the compounds having a non-centrosymmetric space group have a larger band gap than the centrosymmetric space group and thus have more SHG properties. Compounds with large band gaps also have the distinctive S⋯O interaction, contributing significantly to conformational control of the crystal's geometry. [ABSTRACT FROM AUTHOR]

Structure-directing synthesis, such as by the template method, allows us to control the porous structure and morphological properties of solid-state materials. Traditionally, molecules and zero-, one-, and three-dimensional materials have been used as structure-directing agents and templates. Recently, two-dimensional materials (e.g., graphene oxide and graphitic carbon nitride) have been investigated for their use in the synthesis of nanostructured materials. In this study, we used carbon nitride as the structure-directing agent for controlling SiO2 and cupric oxide (CuO) formation in the development of porous CuO–SiO2 nanocomposites via the calcination of a mixture of Cu2+, polyhedral oligomeric silsesquioxane (POSS), and carbon nitride to solve the problems with CuO (e.g., porosity control and low efficiency per weight relative to light materials). Further, we investigated the formation factors of the nanocomposites using comparative experiments to understand the roles of Cu2+, POSS, and carbon nitride. During calcination, carbon nitride induced the formation of SiO2, which supported CuO; the effect of Cu species removed carbon nitride. Subsequently, porous CuO–SiO2 nanocomposites were constructed. The constructed CuO–SiO2 nanocomposites presented a unique morphology (i.e., a fluffy structure), high surface area, and narrow optical band gap. The demonstrated method may pave the way for the design of CuO composite materials and the development of their application as adsorbents and catalysts. [ABSTRACT FROM AUTHOR]

The synthesis, characterization and photocatalytic hydrogen evolution reaction (HER) performance of a series of metal–organic gels (MOGs) constructed from titanium(IV)-oxo clusters and dicarboxylato linkers (benzene-1,4-dicarboxylato and 2-aminobenzene-1,4-dicarboxylato) are described. All the MOGs exhibit a microstructure comprised of metal–organic nanoparticles intertwined into a highly meso-/macroporous structure, as demonstrated by cryogenic transmission electron microscopy and gas adsorption isotherms. Comprehensive chemical characterization enabled the estimation of the complex formula for these defective materials, which exhibit low crystallinity and linker vacancies. To gain deeper insights into the local structure, X-ray absorption fine structure (XAFS) spectroscopy experiments were performed and compared to that of the analogous crystalline metal–organic framework. Additionally, the ultraviolet–visible absorption properties and optical band gaps were determined from diffuse reflectance spectroscopy data. The MOGs were studied as light absorbers for the sacrificial photocatalytic HER under simulated solar light irradiation using a platinum co-catalyst by either (1) in situ photodeposition or (2) ex situ doping process, through a post-synthetic metalation of the MOG structure. The chemical analysis of the metalation, along with high-angle annular dark-field scanning transmission electron microscopy, revealed that although the in situ addition of the co-catalyst led to greater HER rates (227 vs. 110 μmolH2 gMOG−1 h−1 for in situ and ex situ, respectively), the ex situ modification provided a finer distribution of platinum nanoparticles along the porous microstructure and, as a result, it led to a more efficient utilization of the co-catalyst (45 vs. 110 mmolH2 gPt−1 h−1). [ABSTRACT FROM AUTHOR]

An air-stable B3,N3-containing dibenzobisanthene (8) was prepared in 29% yield by heating a 1,3,5-tri(azasilaanthryl)benzene (5) with BBr3 (180 °C). Under these conditions, the reaction does not stop after threefold SiMe2/BBr exchange but proceeds further via two rearrangement and two intramolecular C–H borylation steps. Some mechanistic details were unveiled by using smaller model systems and applying lower reaction temperatures. According to X-ray crystallography, compound 8 has a helically distorted scaffold. Due to its multiple resonance structure, it shows a narrow-band blue-green emission (λem = 493 nm; ΦPL = 84%; FWHM = 0.20 eV; THF); samples measured in PMMA gave prompt and delayed fluorescence lifetimes of 10.7 ns and 136 μs, respectively. The optical properties of 8 and of structurally related species were also investigated by quantum-chemical means: most of these compounds exhibit a small energy gap ΔEST between the lowest excited singlet (S1) and triplet (T1) states and a non-negligible spin–orbit coupling (SOC) between S1 and T1/T2, demonstrating their potential as thermally activated delayed fluorescence (TADF) emitters. [ABSTRACT FROM AUTHOR]

This study reports an efficient synthetic approach towards processable soft conducting nanowires of 2,5-diphenyl-2H-1,2,3-triazole-4-carbonyl appended to L-phenylalanine (1). Using diverse experimental techniques, we demonstrate that, compared to EtOH or EtOH/water, ACN and ACN/water solution produced better hexagonal nanowires of compound 1. The hexagonal nanowires exhibit excellent electron-transfer properties. The ACN or ACN/water solution assembly is mainly governed by hydrogen bonding and π-stacking interactions, favoring -sheet formation and leading to long tubes. The tubes grown in ACN/water are more conducting than the tubes from pure ACN. The tubes grown in ACN/water can carry 100 nA current upon application of a voltage of 0.56 V. The ideal chemical arrangement maximizes the electronic coupling between the π–π overlapping triazole molecules, and produces a band gap of 3.70 eV, as determined by a Tauc plot utilizing UV-visible absorption data. [ABSTRACT FROM AUTHOR]