Search Results (431)

The northern part of the Naomugeng Sag in the Erlian Basin shows favorable sandstone-type uranium mineralization in the lower member of the Saihan Formation. The sandstone thickness ranges from 39.67 to 140.36 m, with an average sand content ratio of 76.33%, indicating broad prospecting potential. This study focuses on samples from uranium ore holes and uranium-mineralized holes in the area, conducting grain-size analysis of uranium-bearing sandstones, heavy mineral assemblage analysis, and detrital zircon U-Pb dating to systematically investigate provenance characteristics. The results indicate that the uranium-bearing sandstones in the lower member of the Saihan Formation were primarily transported by rolling and suspension, characteristic of braided river channel deposits. The heavy mineral assemblage is dominated by zircon + limonite + garnet + ilmenite, suggesting that the sedimentary provenance is mainly composed of intermediate-acid magmatic rocks with minor metamorphic components. Detrital zircon U-Pb ages are mainly concentrated in the ranges of 294–217 Ma (Early Permian to Late Triassic), 146–112 Ma (Middle Jurassic to Early Cretaceous), 434–304 Ma (Late Carboniferous to Early Permian), and 495–445 Ma (Middle–Late Ordovician to Early Silurian). Combined with comparisons of the ages of surrounding rock masses, the provenance of the uranium-bearing sandstones is mainly derived from intermediate-acid granites of the Early Permian–Late Triassic and Middle Jurassic–Early Cretaceous periods in the southern part of the Sonid Uplift, with minor contributions from metamorphic and volcanic rock fragments. The average zircon uranium content is 520.53 ppm, with a Th/U ratio of 0.73, indicating that the provenance not only supplied detrital materials but also provided uranium-rich rock bodies that contributed essential metallogenic materials for uranium mineralization. This study offers critical insights for regional prospecting and exploration deployment. Full article

Metalloporphyrin-based covalent organic frameworks (MPor-COFs) are emerging porous crystalline materials that combine the optoelectronic properties of metalloporphyrins with the highly ordered structure of COFs. Such a combination not only extends the light absorption spectrum of COFs by incorporating porphyrins but also improves the separation and transport capabilities of photo-generated electrons and holes by leveraging the structural advantages of organic frameworks. At the same time, the metal ions embedded in the porphyrin ring provide abundant active sites and optimize charge transfer channels, showing particular advantages in photocatalysis. The molecular design, construction, and photocatalytic application of MPor-COFs were reviewed in this paper. The intrinsic relationship among the structure, optoelectronic properties, and specific photocatalytic application received special attention. First, the role of the metal center in regulating the electronic structure and photophysical property of porphyrin monomers was introduced, as well as the impact of bond type on framework stability and charge transport efficiency. Then, the synthesis strategies for MPor-COFs were summarized. Finally, the applications of these materials in photocatalysis were critically reviewed, and their prospects and challenges in energy conversion and environmental remediation were also discussed. Full article

The increasing impact of global warming is predominantly driven by the extensive use of fossil fuels, which release significant amounts of greenhouse gases into the atmosphere. This has led to a critical need for alternative, sustainable energy sources that can mitigate environmental impacts. Photovoltaic technology has emerged as a promising solution by harnessing renewable energy from the sun, providing a clean and inexhaustible power source. Perovskite solar cells (PSCs) are a class of hybrid organic–inorganic solar cells that have recently attracted significant scientific attention due to their low cost, relatively high efficiency, low–temperature processing routes, and longer carrier lifetimes. These characteristics make them a viable alternative to traditional fossil fuels, reducing the carbon footprint and contributing to the fight against global warming. In this study, the SCAPS–1D numerical simulator was used in the computational analysis of a PSC device with the configuration FTO/ETL/BaZr(S_0.6Se_0.4)₃/HTL/Ir. Different hole transport layer (HTL) and electron transport layer (ETL) material were proposed and tested. The HTL materials included copper (I) oxide (Cu₂O), 2,2′,7,7′–Tetrakis(N,N–di–p–methoxyphenylamine)9,9′–spirobifluorene (spiro–OMETAD), and poly(3–hexylthiophene) (P₃HT), while the ETLs included cadmium suphide (CdS), zinc oxide (ZnO), and [6,6]–phenyl–C₆₁–butyric acid methyl ester (PCBM). Finally, BaZr(S_0.6Se_0.4)₃ was proposed as an absorber, and a fluorine–doped tin oxide glass substrate (FTO) was proposed as an anode. The metal back contact used was iridium. Photovoltaic parameters such as short circuit density (I_sc), open circuit voltage (V_oc), fill factor (FF), and power conversion efficiency (PCE) were used to evaluate the performance of the device. The initial simulated primary device with the configuration FTO/CdS/BaZr(S_0.6Se_0.4)₃/spiro–OMETAD/Ir gave a PCE of 5.75%. Upon testing different HTL materials, the best HTL was found to be Cu₂O, and the PCE improved to 9.91%. Thereafter, different ETLs were also inserted and tested, and the best ETL was established to be ZnO, with a PCE of 10.10%. Ultimately an optimized device with a configuration of FTO/ZnO/BaZr(S_0.6Se_0.4)₃/Cu₂O/Ir was achieved. The other photovoltaic parameters for the optimized device were as follows: FF = 31.93%, J_sc = 14.51 mA cm⁻², and V_oc = 2.18 V. The results of this study will promote the use of environmentally benign BaZr(S_0.6Se_0.4)₃–based absorber materials in PSCs for improved performance and commercialization. Full article

Metal halide perovskite (MHP)-based heterojunctions have become a forefront area in the research of optoelectronic functional materials due to their unique layered crystal structure, tunable band gaps, and exceptional optoelectronic properties. Recent studies have demonstrated that interface charge transfer is a crucial factor in determining the optoelectronic performance of the heterojunction devices. By constructing heterojunctions between MHPs and two-dimensional (2D) materials such as graphene, MoS₂, and WS₂, efficient electron–hole separation and transport can be achieved, significantly extending carrier lifetimes and suppressing non-radiative recombination. This results in enhanced response speed and energy conversion efficiency in photodetectors, photovoltaic devices, and light-emitting devices (LEDs). In these heterojunctions, the thickness of the MHP layer, interface defect density, and band alignment significantly influence carrier dynamics. Furthermore, techniques such as interface engineering, molecular passivation, and band engineering can effectively optimize charge separation efficiency and improve device stability. The integration of multilayer heterojunctions and flexible designs also presents new opportunities for expanding the functionality of high-performance optoelectronic devices. In this review, we systematically summarize the charge transfer mechanisms in MHP-based heterojunctions and highlight recent advances in their optoelectronic applications. Particular emphasis is placed on the influence of interfacial coupling on carrier generation, transport, and recombination dynamics. Furthermore, the ultrafast dynamic behaviors and band-engineering strategies in representative heterojunctions are elaborated, together with key factors and approaches for enhancing charge transfer efficiency. Finally, the potential of MHP heterojunctions for high-performance optoelectronic devices and emerging photonic systems is discussed. This review aims to provide a comprehensive theoretical and experimental reference for future research and to offer new insights into the rational design and application of flexible optoelectronics, photovoltaics, light-emitting devices, and quantum photonic technologies. Full article

This study investigates the feasibility of adding gold nanoparticles (Au-NPs) to vanadium oxide (V₂O_x) serving the hole transport layer (HTL) material oin polymer solar cells to enhance cell performance. The first part of this study used Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) as a baseline and optimized the parameters of this HTL material. Then, the V₂O_x was substituted as the HTL material, and its parameters were optimized again. The second part involved incorporating an aqueous solution of gold nanoparticles (Au-NPs) with an average particle size of approximately 80 nm into V₂O_x. Due to the excitation of localized surface plasmon resonance (LSPR) by Au-NPs, the addition of Au-NPs to the V₂O_x layer can enhance the absorption efficiency of the P3HT:PCBM blended film. Therefore, compared with V₂O_x alone, the solar cells with Au-NPs incorporated into the V₂O₅ hole transport layer demonstrate improved power conversion efficiency (PCE). Full article

The functional integration of chiral liquid crystals and π-conjugated compounds has great potential for creating novel exotic materials. A series of chiral donor–acceptor (D–A)-type fluorenone derivatives was synthesized to investigate the influence of molecular structure upon their liquid-crystalline phase-transition behavior, ferroelectricity, photophysical properties, and photoconductive properties. Polarizing optical microscopy (POM), differential scanning calorimetry (DSC), and X-ray diffraction (XRD) analyses revealed that several D–A-type fluorenone derivatives exhibited liquid crystal (LC) phases. These chiral LC fluorenone derivatives exhibited polarization hysteresis in the chiral smectic C (SmC*) phase. Among the four fluorenone-based ferroelectric liquid crystals (FLCs), (R,R)-2a exhibited the largest spontaneous polarization (over 3.0 × 10² nC cm⁻²). The formation of intramolecular charge-transfer (ICT) states in each compound was evidenced by the UV–vis absorption spectroscopy. Ambipolar carrier transport in the SmC* phases of the fluorenone-based FLCs was elucidated by the time-of-flight (TOF) method. The mobilities of holes and electrons in the SmC* phases were on the order of 10⁻⁵ cm² V⁻¹ s⁻¹, which is on par with the carrier mobilities of low-ordered smectic phases in conventional LC semiconductors. Full article

In this work the authors analyze a CdS/SnSe solar cell using a SnTe as a hole transport layer. We analyzed the impact of the recombination mechanisms namely radiative, and Shockley–Read–Hall in the bulk and at the interfaces using SCAPS-1D software and the impact of SnSe and CdS layer thickness. Additionally, the effect of concentration of acceptors and bulk defects in SnTe and SnSe on the performance were studied. The conditions that optimize device performance are presented. The results of the present study suggest that using a SnTe hole transport layer can result in an efficiency promotion from 0.7% to 24.48%. Full article

Cu₂O solar cells are regarded as a promising emerging inorganic photovoltaic technology due to their power conversion efficiency (PCE) potential and material sustainability. While previous studies primarily focused on the band offset between n-type buffer layers and Cu₂O optical absorption, this work systematically investigated an ETL/buffer/p-Cu₂O/HTL heterojunction structure using SCAPS-1D simulations. Key design parameters, including bandgap (Eg) and electron affinity (χ) matching across layers, were optimized to minimize carrier transport barriers. Furthermore, the doping concentration and thickness of each functional layer (ETL: transparent conductive oxide; HTL: hole transport layer) were tailored to balance electron conductivity, parasitic absorption, and Auger recombination. Through this approach, a maximum PCE of 14.12% was achieved (V_oc = 1.51V, J_sc = 10.52 mA/cm², FF = 88.9%). The study also identified candidate materials for ETL (e.g., GaN, ZnO:Mg) and HTL (e.g., ZnTe, NiO_x), along with optimal thicknesses and doping ranges for the Cu₂O absorber. These findings provide critical guidance for advancing high-performance Cu₂O solar cells. Full article

This study provides a comprehensive investigation into the growth behavior of boron nitride (BN) buffer layers on Silicon carbide (SiC) substrates and their influence on interfacial band alignment. BN layers were deposited on semi-insulating SiC by RF magnetron sputtering with deposition times of 2.5, 5, and 7.5 min (these deposition times are specific experimental parameters to adjust the thickness of the amorphous BN layer, not intrinsic material properties of BN). Atomic force microscopy revealed that the surface roughness of the BN layers initially decreased and then increased with thickness, indicating an evolution from nucleation to continuous film formation, followed by surface coarsening. Transmission electron microscopy confirmed the BN thicknesses of approximately 3.25, 4.91, and 7.57 nm, showing that the layers gradually became uniform and compact, thereby improving the structural integrity of the BN/SiC interface. Band alignment was analyzed using the Kraut method, yielding a valence band offset of ~0.36 eV and a conduction band offset of ~2.34 eV for the BN/SiC heterojunction. This alignment indicates that the BN buffer layer introduces a pronounced electron barrier, effectively suppressing leakage, while the relatively small VBO facilitates hole transport across the interface. These findings demonstrate that the BN buffer layer enhances interfacial bonding, reduces defect states, and enables band structure engineering, offering a promising strategy for improving the performance of wide-bandgap semiconductor devices. Full article

Bilayer transition metal dichalcogenides (TMDs) are promising materials for next-generation field-effect transistors (FETs) due to their atomically thin structure and favorable transport properties. In this study, we employ density functional theory (DFT) to compute the electronic band structures and phonon dispersions of bilayer WS₂, WSe₂, and MoS₂, and the electron-phonon scattering rates using the EPW (electron-phonon Wannier) method. Carrier transport is then investigated within a semiclassical full-band Monte Carlo framework, explicitly including intrinsic electron-phonon scattering, dielectric screening, scattering with hybrid plasmon–phonon interface excitations (IPPs), and scattering with ionized impurities. Freestanding bilayers exhibit the highest mobilities, with hole mobilities reaching 2300 cm²/V·s in WS₂ and 1300 cm²/V·s in WSe₂. Using hBN as the top gate dielectric preserves or slightly enhances mobility, whereas HfO₂ significantly reduces transport due to stronger IPP and remote phonon scattering. Device-level simulations of double-gate FETs indicate that series resistance strongly limits performance, with optimized WSe₂ pFETs achieving ON currents of 820 A/m, and a 10% enhancement when hBN replaces HfO₂. These results show the direct impact of first-principles electronic structure and scattering physics on device-level transport, underscoring the importance of material properties and the dielectric environment in bilayer TMDs. Full article

This study presents a computational investigation into the design of triphenylamine-based donor chromophores incorporating 2-(1,1-dicyanomethylene)rhodanine as the acceptor unit. Three molecular architectures (System-1 to System-3) were developed by introducing distinct thiophene-derived $\pi$-bridges to modulate their electronic and optical characteristics for potential application in bulk heterojunction organic solar cells (OSCs). Geometrical optimizations were performed at the B3LYP/6-31+G(d,p) level, while excited-state and absorption properties were evaluated using TD-DFT with the CAM-B3LYP functional. Frontier orbital analysis revealed efficient charge transfer from donor to acceptor moieties, with System-3 showing the narrowest HOMO–LUMO gap (1.96 eV) and the lowest excitation energy (2.968 eV). Charge transport properties, estimated from reorganization energies, indicated that System-2 exhibited the most favorable balance for ambipolar transport, featuring the lowest electron reorganization energy (0.317 eV) and competitive hole mobility. Photovoltaic parameters calculated with PC₆₁BM as acceptor predicted superior $V_{oc}$, $J_{sc}$, and fill factor values for System-2, resulting in the highest theoretical power conversion efficiency (10.95%). These findings suggest that $\pi$-bridge engineering in triphenylamine-based systems can significantly enhance optoelectronic performance, offering promising donor materials for next-generation OSC devices. Full article

Perovskite solar cells (PSCs) have emerged as promising photovoltaic technologies owing to their high power conversion efficiency (PCE) and material versatility. Conventional optimization of PSC architectures largely depends on iterative experimental approaches, which are often labor-intensive and time-consuming. In this study, a data-driven modeling strategy is introduced to accelerate the design of efficient and mechanically robust PSCs. Seven supervised regression models were evaluated for predicting key photovoltaic parameters, including PCE, short-circuit current density (Jsc), open-circuit voltage (Voc), and fill factor (FF). Among these, a stacking ensemble framework exhibited superior predictive accuracy, achieving an R² of 0.8577 and a root mean square error of 2.084 for PCE prediction. Model interpretability was ensured through Shapley Additive exPlanations(SHAP) analysis, which identified precursor solvent composition, A-site cation ratio, and hole-transport-layer additives as the most influential parameters. Guided by these insights, ten device configurations were fabricated, achieving a maximum PCE of 24.9%, in close agreement with model forecasts. Furthermore, multiscale mechanical assessments, including bending, compression, impact resistance, peeling adhesion, and nanoindentation tests, were conducted to evaluate structural reliability. The optimized device demonstrated enhanced interfacial stability and fracture resistance, validating the proposed predictive–experimental framework. This work establishes a comprehensive approach for performance-oriented and reliability-driven PSC design, providing a foundation for scalable and durable photovoltaic technologies. Full article

Internal erosion is a significant issue caused by water flow within soils, resulting in structural collapse of hydraulic structures, particularly in coarse soils located near rivers. These soils typically exhibit granulometric instability due to low clay content, resulting in poor hydraulic and mechanical properties. To mitigate this problem, cement treatment is applied as an alternative to soil removal, reducing transportation and storage costs. The hole erosion test (HET) and Crumbs tests, shearing behaviour through consolidated undrained (CU) triaxial, and microstructure analyses regarding scanning electron microscopy (SEM), mercury intrusion porosimeter (MIP) and thermogravimetric analysis (TGA) were conducted for untreated and treated coarse soil specimens with varying cement contents (1%, 2%, and 3%) and curing durations (1, 7, and 28 days). The findings indicate a reduction in the loss of eroded particles and overall stability of treated soils, along with an improvement in mechanical properties. SEM observations reveal the development of hydration gel after treatment, which enhances cohesion within the soil matrix, corroborated by TGA analyses. MIP reveals the formation of a new class of pores, accompanied by a reduction in dry density. This study demonstrates that low cement addition can transform locally unsuitable soils into durable construction materials, reducing environmental impact and supporting sustainable development. Full article

Lead-free perovskite solar cells (PSCs) provide a viable alternative to lead-based versions, thereby reducing significant environmental issues related to toxicity. MASnIBr₂ has emerged as a very attractive lead-free perovskite material due to its environmentally friendly characteristics and advantageous optoelectronic capabilities. However, more tuning is required to achieve superior conversion efficiencies (PCEs). This study uses SCAPS-1D simulations to systematically develop and optimize the electron and hole transport layers (ETLs/HTLs) in MASnIBr₂-based perovskite solar cells (PSCs). Iterative simulations are used to carefully examine and optimize critical parameters, including electron affinity, energy bandgap, layer thickness, and doping density. Additionally, the thickness of the MASnIBr₂ absorber layer is optimized to enhance charge extraction and light absorption. Our findings showed a maximum power conversion efficiency of 20.42%, an open-circuit voltage of 1.38 V, a short-circuit current density of 17.91 mA/cm², and a fill factor of 82.75%. This study establishes a basis for future progress in sustainable photovoltaics and offers essential insights into the design of efficient lead-free perovskite solar cells. Full article

Transition-metal oxides (TMOs) possess pronounced optoelectronic properties and are widely exploited in photovoltaics and photocatalysis. Here, we introduce a hot wire oxidation sublimation deposition (HWOSD) that directly converts elemental Mo and W into amorphous MoO_x and WO_x films on various substrates. Scanning electron microscopy and atomic force microscopy reveal uniform thickness and conformal coverage over textured and planar surfaces. X-ray photoelectron spectroscopy indicates high oxygen contents with stoichiometric ratios of 2.94 (MoO_x) and 2.91 (WO_x). Optical measurements show transmittances > 94% across 400–1200 nm, yielding optical band gaps of 1.86 eV (MoO_x) and 2.67 eV (WO_x). The conductivities of MoO_x and WO_x were 2.58 × 10⁻⁶ S cm⁻¹ and 5.14 × 10⁻⁷ S cm⁻¹ at room temperature, and the TMO/Si surface potential differences are 200 mV and 114 mV, respectively. Minority-carrier-lifetime measurements indicate that MoO_x films confer an additional passivation benefit to the i a-Si:H/c-Si/i a-Si:H stack. Annealing of MoO_x and WO_x realized their phase transition from an amorphous state to a polycrystalline state, with changes in their optical transmittance in the visible light region. Investigation of the photovoltaic performances of MoO_x and WO_x as HTLs deposited by HWOSD demonstrates their excellent electronic functionality in optoelectronics. These results establish HWOSD as a scalable, low-temperature method to fabricate high-quality TMO films and expand their potential in advanced optoelectronic devices. Full article