Search

Researchers have created a modern infrared (IR) sensor that is both super-sensitive and highly flexible. This remarkable device possesses impressive properties of exceptional sensitivity (24,000%), high responsiveness (1.25 A/W), and fast response time (3 ms). This innovation stands out for its unique construction: an ultrathin layer of lead sulfide (PbS) deposited on a standard Whatman filter paper. This design achieves a photo-current 32 times greater than previous record-holding PbS thin films. The key advantage is its unmatched flexibility. This sensor can bend and flex without breaking, maintaining its IR detection capabilities even after enduring extreme bending cycles. This breakthrough paves the way for a new era of wearable IR photo sensors, flexible electronics, and medical applications. [ABSTRACT FROM AUTHOR]

This study employs microwave roasting to decompose smithsonite mineral (zinc carbonate) into zinc oxide, which then reacts with pyrite to sulfurize its surface, forming zinc sulfide. This process is beneficial for the flotation recovery of zinc oxide minerals. The surface sulfidation behavior of smithsonite under low-temperature microwave roasting conditions is examined through X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and thermodynamic calculations. XRD and thermodynamic analysis indicate that smithsonite completely decomposes into zinc oxide at 400 °C. Introducing a small amount of pyrite as a sulfidizing reagent leads to the formation of sulfides on the surface of decomposed smithsonite. XPS analysis confirms that the sulfide formed on the surface is zinc sulfide. SEM analysis reveals that sulfides are distributed on the surface of smithsonite, and the average sulfur concentration increases with the pyrite dosage. Microwave-assisted sulfurization of smithsonite (ZnCO3) was found to significantly enhance its floatability compared to conventional sulfurization methods. The optimal mass ratio of ZnCO3 to FeS2 is approximately 1:1.5, with the best temperature being 400 °C. These findings provide a technical solution for the application of microwave roasting in the efficient recovery of smithsonite through flotation. [ABSTRACT FROM AUTHOR]

This paper presents the results of a study of the mineralogical and chemical composition of zinc and lead metallurgical slags. These slags contain numerous elements, including toxic metals, which form conglomerates or multiphase intergrowths. The phase composition of slags is one of the main factors that determine their behaviour in weathering environments, that is, their ability to release metals when exposed to atmospheric factors. In this paper, the release of elements from slags and their mobility in a hypergenic environment is determined based on the results of leachability tests and on geochemical modelling, thus assessing the environmental impact of landfilled slags. The elements released from slags in the largest quantities are zinc and lead. Zn is leached out over a long period of time. It was found that after 12 years, the concentration of Zn in the eluate exceeds by 40 times the permissible value of 200 mg/kg for hazardous waste. The degree of leaching of lead from slags as a function of time (after 12 years), despite its significant solubility in water, is much lower than the degree of leaching of zinc. The most mobile phase components of slags in the studied hypergenic environment are the lead phases (anglesite and galena) and, to a lesser extent, the zinc phases (sphalerite and willemite). Anglesite and galena in almost the entire Eh-pH range, along with admixtures of elements, decompose into ionic forms: PbCl42−, Pb2+, and PbOH+. Sphalerite in the soil and water environment (oxidizing and acidic conditions) will decompose into the mobile ionic form Zn2+. Willemite, which is resistant to weathering, will undergo similar decomposition. It can therefore be assumed that the carriers of toxic metals are primarily lead sulphides and sulphates, zinc sulphides, and, less frequently, zinc, lead, and iron oxides. [ABSTRACT FROM AUTHOR]

Cerussite is an essential lead oxide mineral with increasing economic importance as lead sulfide resources deplete. This study utilizes density functional theory (DFT) to investigate the structural and electronic properties of the sulfurized cerussite (110) surface. The results show that when the cerussite crystal cleaves along the (110) plane, only the surface layer atoms undergo relaxation to reconstruct the surface, while the atoms located deeper have almost no impact on the reconstructed surface structure. The Pb atoms on the cerussite (110) surface react with the sulfurizing agent to form a PbS deposition layer with a structure similar to galena. This PbS deposition layer is tightly adsorbed onto the lead oxide layer through Pb-S bonds formed by S and subsurface lead oxide structure Pb atoms. The chemical reactivity of Pb atoms in the PbS layer on the sulfurized cerussite (110) surface is more potent than that of Pb atoms on the galena surface; additionally, the Pb atoms closer to the lead oxide layer exhibit slightly higher chemical reactivity than those farther away. This study provides insight into sulfurized cerussite surfaces' structure and properties at an atomic level and assists in explaining the floating behavior of cerussite. [ABSTRACT FROM AUTHOR]

Colloidal semiconductor nanoparticles (NPs) represent an emergent state of matter with unique properties, bridging bulk materials and molecular structures. Their distinct physical attributes, such as bandgap and photoluminescence, are intricately tied to their size and morphology. Ligand passivation plays a crucial role in shaping NPs and determining their physical properties. Ligand exchange (LE) offers a versatile approach to tailoring NP properties, often guided by Pearson's Hard–Soft Acid–Base theory. Lead sulfide (PbS), a semiconductor of considerable interest, exhibits size-dependent tunable bandgaps from the infrared to the visible range. Here, we present two methods for synthesizing water-soluble, polyvinylpyrrolidone (PVP)-coated PbS NPs. The first involves direct synthesis in an aqueous solution while utilizing PVP as the surfactant for the formation of nano-cubes with a crystal coherence length of ~30 nm, while the second involves LE from octadecylamine-coated PbS truncated nano-cubes to PVP-coated PbS NPs with a crystal coherence length of ~15 nm. Multiple characterization techniques, including X-ray diffraction, transmission electron microscopy, Fourier-transform infrared spectroscopy, and thermal gravimetric analysis, confirmed the results of the synthesis and allowed us to monitor the ligand exchange process. Our findings demonstrate efficient and environmentally friendly approaches for synthesizing PVP-coated PbS NPs. [ABSTRACT FROM AUTHOR]

In this study, we investigated the influence of Cu doping and gamma irradiation on the photocatalytic activity of lead sulfide (PbS) nanoparticles for methylene blue (MB) degradation under solar light. The optical bandgap of the γ-irradiated Pb (1-x) Cu x S (where x = 0 to 0.02) was calculated between 2.29 eV - 2.72 eV, facilitating the modulation of optical bandgaps in PbS. Additional analyses incorporating photoluminescence and the Brunauer (Emmett) Teller method were used to determine optical properties, surface area, and pore distribution. The photocatalytic degradation of MB under sunlight irradiation was investigated. The photocatalytic activity was enhanced with the increasing rate of MB degradation. Notably, gamma-irradiated Pb 0.99 Cu 0.01 S exhibited a remarkable MB degradation efficiency of 73.64 %, demonstrating its stability over three consecutive cycles. This underscores its inherent stability and potential for repeated use. Overall, these findings highlight the significant potential of gamma-irradiated Cu-doped PbS nanoparticles as durable, renewable photocatalysts for efficient degradation in an aqueous media, thereby offering a promising approach for environmental remediation. [ABSTRACT FROM AUTHOR]

Ultrathin cells are gaining popularity due to their lower weight, reduced cost, and enhanced flexibility. However, compared to bulk cells, light absorption in ultrathin cells is generally much lower. This study presents a numerical simulation of a metamaterial light management structure made of ultrathin lead sulfide colloidal quantum dots (PbS CQDs) sandwiched between a top ITO grating and a tungsten backing to develop an efficient hybrid solar/thermophotovoltaic cell (HSTPVC). The optical properties were computed using both the finite integration technique (FIT) and the finite element method (FEM). The absorptance enhancement was attributed to the excitations of magnetic polaritons (MP), surface plasmon polaritons (SPP), and lossy mode resonance (LMR). The HSTPVC with the metamaterial optical light management structure was assessed for short-circuit current density, open-circuit voltage, and conversion efficiency. The results show a conversion efficiency of 18.02% under AM 1.5 solar illumination and a maximum thermophotovoltaic conversion efficiency of 12.96% at TB = 1600 K. The HSTPVC can operate in a hybrid solar/thermal conversion state when the ITO grating is included by combining the advantages of QDs and metamaterials. This work highlights the potential for developing a new generation of hybrid STPV cells through theoretical modeling and numerical simulations. [ABSTRACT FROM AUTHOR]

Silicon photonics faces a persistent challenge in extending photodetection capabilities beyond the 1.6 µm wavelength range, primarily due to the lack of appropriate epitaxial materials. Colloidal quantum dots present a promising solution here, offering distinct advantages, such as infrared wavelength tunability, cost-effectiveness, and facile deposition. Their unique properties position them as a potential candidate for enabling photodetection in silicon photonics beyond the conventional telecom wavelength, thereby expanding the potential applications and capabilities within this domain. In this study, we have successfully integrated lead sulfide (PbS) colloidal quantum dot photodiodes (QDPDs) onto silicon waveguides using standard process techniques. The integrated photodiodes exhibit a remarkable responsivity of 1.3 A/W (with an external quantum efficiency of 74.8%) at a wavelength of 2.1 µm, a low dark current of only 106 nA, and a bandwidth of 1.1 MHz under a −3 V bias. To demonstrate the scalability of our integration approach, we have developed a compact 8-channel spectrometer incorporating an array of QDPDs. This achievement marks a significant step toward realizing a cost-effective photodetector solution for silicon photonics, particularly tailored for a wide range of sensing applications around the 2 µm wavelength range. [ABSTRACT FROM AUTHOR]

The integration between infrared detection and modern microelectronics offers unique opportunities for compact and high-resolution infrared imaging. However, silicon, the cornerstone of modern microelectronics, can only detect light within a limited wavelength range (< 1100 nm) due to its bandgap of 1.12 eV, which restricts its utility in the infrared detection realm. Herein, a photo-driven fin field-effect transistor is presented, which breaks the spectral response constraint of conventional silicon detectors while achieving sensitive infrared detection. This device comprises a fin-shaped silicon channel for charge transport and a lead sulfide film for infrared light harvesting. The lead sulfide film wraps the silicon channel to form a “three-dimensional” infrared-sensitive gate, enabling the photovoltage generated at the lead sulfide-silicon junction to effectively modulate the channel conductance. At room temperature, this device realizes a broadband photodetection from visible (635 nm) to short-wave infrared regions (2700 nm), surpassing the working range of the regular indium gallium arsenide and germanium detectors. Furthermore, it exhibits low equivalent noise powers of 3.2×10−12 W·Hz−1/2 and 2.3×10−11 W·Hz−1/2 under 1550 nm and 2700 nm illumination, respectively. These results highlight the significant potential of photo-driven fin field-effect transistors in advancing uncooled silicon-based infrared detection.

In this study, lead(II) sulphide (PbS) nanoparticles of varying particle sizes were synthesized using the hot injection method, employing 1-octadecene (ODE) as a coordinating ligand in conjunction with oleylamine (OAm). This synthesis approach was compared with the preparation of hexagonal-shaped nanoparticles through the ligand of 1-Dodecanethiol (DT), resulting in DT-capped PbS nanoparticles. The prepared nanoparticles were characterized using multiple techniques including photoluminescence (PL), transmission electron microscopy (TEM), X-ray diffraction (XRD), and Fourier-transform infrared spectroscopy (FT-IR). The condensation reaction of DT ligands led to various nanoparticles within the range of 34.87 nm to 35.87 nm across different synthesis temperatures (120 °C, 150 °C, 180 °C, 210 °C, and 240 °C). The PbS with DT ligands exhibited a highly crystalline and superhydrophilic structure. Interestingly, near-infrared (NIR)-PL analysis revealed peaks at 1100 nm, representing the lowest-energy excitonic absorption peak of PbS nanoparticles for both ligands. This suggests their potential utility in various applications, including IR photoreactors, as well as in the development of non-toxic nanoparticles for potential applications in in vivo bioimaging. [ABSTRACT FROM AUTHOR]

Herein, the synthesis of vanadium sulfide (VxSy) by atomic layer deposition (ALD) based on the use of tetrakis(dimethylamino) vanadium (IV) and hydrogen sulfide is presented for the first time. The (ultra)thin films VxSy are synthesized in a wide range of temperatures (100–225 °C) and extensively characterized by different methods. The chemical composition of the VxSy (ultra)thin films reveals different vanadium oxidation states and sulfur‐based species. Extensive X‐ray photoelectron spectroscopy analysis studies the effect of different ALD parameters on the VxSy chemical composition. Encouraged by the rich chemistry properties of vanadium‐based compounds and based on the variable valences of vanadium, the electrochemical properties of ALD VxSy (ultra)thin films as electrode material for supercapacitors are further explored. Thereby, nanotubular composites are fabricated by coating TiO2 nanotube layers (TNTs) with different numbers of VxSy ALD cycles at low temperature (100 °C). Long‐term cycling tests reveal a gradual decline of electrochemical performance due to the progressive VxSy thin films dissolution under the experimental conditions. Nevertheless, VxSy‐coated TNTs exhibit significantly superior capacitance properties as compared to the blank counterparts. The enhanced capacitance properties exhibited are derived from the presence of chemically stable and electrochemically active S‐based species on the TNTs surface. [ABSTRACT FROM AUTHOR]

The present work is devoted to studying the effect of temperature on the formation of a submicron-sized particles of lead sulfide (PbS). Lead sulfide samples were obtained by chemical bath deposition method. 25 ml of an aqueous solution of lead nitrate Pb(NO3)2, 75 ml of sodium hydroxide NaOH and 50 ml of thiourea CH4N2S with molar concentrations of 0.18 M (1.52 g), 0.38 M (1.151 g) and 0.11 M (0.397 g), respectively, were used as reagents. In the process of obtaining samples, solutions of lead nitrate and sodium hydroxide were initially mixed at temperatures of 70℃ and 100℃, then a thiourea solution was added to this mixture. It was found that temperature has an effect on the formation of PbS structures. It is shown that at a temperature of 100℃ isolated particles are formed, whereas at a temperature of 70℃ a film is formed. The morphology and elemental composition of the obtained lead sulfide (PbS) samples were studied by scanning electron microscopy (SEM) and the surface structure was studied using an atomic force microscope (AFM). As a result of the study of the morphology and texture of the surface of lead sulfide samples, the average size of isolated particles was determined, which is ~144 nm, and these particles also had a cubic shape with a smooth surface. [ABSTRACT FROM AUTHOR]

Undoped and Chromium (Cr) doped (2, 4%) copper sulfide (Cu2S) nanostructured thin films were created by spray pyrolysis. The films were polycrystalline and combined cubic and monoclinic structures, according to the results of the XRD investigation. Surface roughness values for the doped and undoped thin films are 8.71, 7.79, and 3.24 nm, respectively. SEM images display Cu2S nanostructures with fine crystallites and traces of nanorod. Chromium doping increases particle size and induces nanorod growth, enhancing surface porosity. The optical examination shows that Cr-doped Cu2S thin films exhibit effective absorption (> 104 orders) in the visible range. From the change in absorption coefficient, it can be observed that there is a valley around 2.6 eV. By doping Cr (up to 2%) in Cu2S films, it is possible to control the band gap between 2.62 eV and 2.73 eV. The refractive index of undoped Cu2S films decreases with increasing Cr-doping concentration. Gas sensing of Chromium-doped and undoped Cu2S nanostructures involves dynamic resistance change at 100°C. Undoped Cu2S displays low resistance, exhibiting p-type semiconductor behavior. Notably, 4% Cr-doped Cu2S shows high resistance, and the introduction of NO2 decreases resistance. Decreased sensitivity with rising Cr doping in Cu2S: 2% Cr and Cu2S: 4% Cr. Responsiveness declined across different NO2 concentrations (200 ppm, 300 ppm, and 400 ppm). [ABSTRACT FROM AUTHOR]

This article deals with the optimization by simulation of a graded bandgap thin film solar cell based on antimony selenosulfide Sb2(Se1-ySy)3 having the following structure: Front contact/n-ZnO/i-ZnO/p-SbSSe/n-CdS/Back contact. The simulation is performed using SCAPS-1D software. The optimization process includes optimizing the bulk defect density, bandgap profile, material composition, thickness, and doping density of the absorber layer of thin film solar cell based on antimony selenosulfide Sb2(Se1-ySy)3. We found that for a bulk defect density below 1013 cm-3, using an absorber material with a graded bandgap profile leads to an efficiency of 25.33 % (For a bulk defect density of 1010 cm-3) higher than that with a uniform bandgap profile. However, for a bulk defect density of 1013 cm-3, both profiles provide almost the same maximum solar cell conversion efficiencies of about 13.6 %. Ultimately, for a bulk defect density above 1013 cm-3, the graded bandgap profile is not useful, and a maximum solar cell conversion efficiency of 10.5 % (For a bulk defect density of 1014 cm-3) is achieved with a uniform bandgap profile. These optimization results help to improve the efficiency of low-cost fabricated thin-film solar cells. [ABSTRACT FROM AUTHOR]

Galena is a natural mineral enriched with lead sulfide (PbS). It typically forms in hydrothermal veins associated with igneous rocks and can also occur as a gangue mineral in other ore deposits. PbS is of special importance for scientific research applications due to the possibility of tuning its semiconductor energy gap using nanotechnology in conjunction with powder metallurgy as an easy, controllable production route. In this paper, almost pure PbS was successfully produced starting from a high ratio of PbS phase galena ore. As-received galena lumps were roughly pulverized and milled to produce four particle size ranges of 38, 63, 125, and 250 µm prior to compaction and sintering in a vacuum (pre-flushed with argon gas). SEM coupled with the EDAX analysis unit was employed to investigate the microstructure and chemical composition of the as-received galena and the subsequent products after sintering. The chemical analysis confirmed the high ratio of PbS compound in the as-received galena and sintered products with approximately 85% Pb and 13% S mass ratio. The sintering process of the galena powder was carried out at different values of temperature, time, and compaction pressure. Additionally, the effect of length to diameter ratio of compacted and sintered samples was investigated. XRD analysis confirmed the existence of the PbS phase in the as-received and sintered samples at 700 °C with approximately 98 wt.%, as well as a new phase that is formed at 800 °C with a lower percentage. The micro-hardness of the as-received and sintered samples was measured and compared with the as-received galena ore. The results showed a significant reduction in the hardness of sintered galena powder compared with the bulk as-received galena by 52%. Furthermore, a relative sintered density of 99.3% for the as-received galena density signifies a novel result using powder metallurgy techniques. [ABSTRACT FROM AUTHOR]

Disclosing the full potential of functional nanomaterials requires the optimization of synthetic protocols and an effective size screening tool, aiming at triggering their size-dependent properties. Here we demonstrate the successful combination of a wide-angle X-ray total scattering approach with a deep learning classifier for quantum dots sizing in both colloidal and dry states. This work offers a compelling alternative to the lengthy process of deriving sizing curves from transmission electron microscopy coupled with spectroscopic measurements, especially in the ultra-small size regime, where empirical functions exhibit larger discrepancies. The core of our algorithm is an all-convolutional neural network trained on Debye scattering equation simulations, incorporating atomistic models to capture structural and morphological features, and augmented with physics-informed perturbations to account for different predictable experimental conditions. The model performances are evaluated using both wide-angle X-ray total scattering simulations and experimental datasets collected on lead sulfide quantum dots, resulting in size classification accuracies surpassing 97%. With the developed deep learning size classifier, we overcome the need for calibration curves for quantum dots sizing and thanks to the unified modeling approach at the basis of the total scattering method implemented, we include simultaneously structural and microstructural aspects in the classification process. This algorithm can be complemented by incorporating input information from other experimental observations (e.g., small angle X-ray scattering data) and, after proper training with the pertinent simulations, can be extended to other classes of quantum dots, providing the nanoscience community with a powerful and broad tool to accelerate the development of functional (nano)materials. [ABSTRACT FROM AUTHOR]

A Pb-free FASnI3 perovskite solar cell improved by using Cu2O/ZnO as two-dimensional-based hole/electron transport nanolayers has been proposed and studied by using a SCAPS-1D solar simulator. To calibrate our study, at first, an FTO/ZnO/MAPbI3/Cu2O/Au multilayer device was simulated, and the numerical results (including a conversion efficiency of 6.06%, an open circuit potential of 0.76 V, a fill factor parameter of 64.91%, and a short circuit electric current density of 12.26 mA/cm2) were compared with the experimental results in the literature. Then, the conversion efficiency of the proposed FASnI3-based solar cell was found to improve to 7.83%. The depth profile energy levels, charge carrier concentrations, recombination rate of electron/hole pair, and the FASnI3 thickness-dependent solar cell efficiency were studied and compared with the results obtained for the MAPbI3-containing device (as a benchmark). Interestingly, the FASnI3 material required to obtain an optimized solar cell is one-half of the material required for an optimized MAPbI3-based device, with a thickness of 200 nm. These results indicate that developing more environmentally friendly perovskite solar cells is possible if suitable electron/hole transport layers are selected along with the upcoming Pb-free perovskite absorber layers. [ABSTRACT FROM AUTHOR]

In recent times, zero-dimensional materials have gained importance from a fundamental and technological perspective. Lead selenium sulphide (PbSeS) is a potential candidate for finding interest in its zero-dimensional form among many compound semiconductors. Hence, in this communication, we explored the impact of quantum confinement effects on the energy band gap and wavelength of PbSeS semiconductor nanocrystals (Quantum dots) using cohesive energy and hyperbolic band models (HBM). Experimental data, such as scanning electron microscopy, UV-Vis-NIR, and PL spectroscopies were used to determine the size of nanoparticles and wavelength. PbSeS nanocrystals were also prepared by one-pot synthesis. The experimental results showed that the prepared PbSeS nanostructures are formed with tiny nanometer size, which showed a redshift of about 0.79eV in energy bandgap. A theoretical study showed that the energy bandgap in quantum-sized PbSeS differs from that in its bulk crystal. [ABSTRACT FROM AUTHOR]

Lead sulfide quantum dots (PbS QDs) are used in broadband photodetectors due to their excellent size tunability, photosensitivity, and solution processability. However, due to the risk of Ostwald ripening, synthesizing high-quality PbS QDs with absorption peaks over 2000 nm with high monodispersity is a challenge. In this study, by controlling the molar ratio of Pb to S and the number of injections of S precursor, we successfully prepared large PbS QDs with an absorption peak at 2122 nm, corresponding to an average diameter of 11.42 nm, with a super-mono-dispersity of 5.50%. Broadband photodetectors ranging from visible light to short-wave infrared are prepared using the large PbS QDs, corresponding to a response rate of 5.98 mA/W at 1940 nm. [ABSTRACT FROM AUTHOR]

In this review, the chemical bath deposition method has been studied to investigate lead sulfide thin film. The important results obtained from XRD, AFM and optical Spectrophotometer measurements were discussed. peaks patterns illustrated that the lead sulfide structure have a cubic phase nanocrystalline corresponded to the strong peaks (111) and (200) at 2θ ≅ 26.3◦ and 29.8◦ respectively. Atomic force microscope (AFM) images exhibited that the lead sulfide (PbS) thin films have a nano-size grain also the grain size increased with increasing film thickness. Different parameters such as dislocation density and internal strain have been studied to be decreased with concentration. Decreasing internal strain and dislocation density with increasing concentration show enhancement of lattice constant as prepared films Scanning electron Microscope (SEM) images displayed that the top surface layers are strongly affected depending on the nature top. The PbS structure are quite homogeneous , the size distribution was about 71–83 nm. The influence of deposition time, thickness, nature of the substrate, concentration of solution and doping on the PbS films was also discussed. It can be seen, The prepared thin film was a thinner film with a short deposition time compared to prepared samples with a longer time. It has also been found that the precipitated films show optical absorbance in the room and UV region but their absorbance decreases upon entering the near-infrared (NIR) region. Lead Sulfide thin films have gained remarkable attention worldwide due to an important narrow band gap semiconductor which has broad potential applications in optoelectronics devices.

The realization of a controllable transparent conducting system with selective light transparency is crucial for exploring many of the most intriguing effects in top‐illuminated optoelectronic devices. However, the performance is limited by insufficient electrical conductivity, low work function, and vulnerable interface of traditional transparent conducting materials, such as tin‐doped indium oxide. Here, it is reported that two‐dimensional (2D) titanium carbide (Ti3C2Tx) MXene film acts as an efficient transparent conducting electrode for the lead sulfide (PbS) colloidal quantum dots (CQDs) photodiode with controllable near infrared transmittance. The solution‐processed interface engineering of MXene and PbS layers remarkably reduces the interface defects of MXene/PbS CQDs and the carrier concentration in the PbS layer. The stable Ti3C2Tx/PbS CQDs photodiodes give rise to a high specific detectivity of 5.51 × 1012 cm W−1 Hz1/2, a large dynamic response range of 140 dB, and a large bandwidth of 0.76 MHz at 940 nm in the self‐powered state, ranking among the most exceptional in terms of comprehensive performance among reported PbS CQDs photodiodes. In contrast with the traditional photodiode technologies, this efficient and stable approach opens a new horizon to construct widely used infrared photodiodes with CQDs and MXenes. [ABSTRACT FROM AUTHOR]

The extremely weak heterointerface construction of high‐entropy materials (HEM) hinders them being the electromagnetic wave (EMW) absorbers with ideal properties. To address this issue, this study proposes multiphase interfacial engineering and results in a multiphase‐induced interfacial polarization loss in multielement sulfides. Through the selection of atoms with diverse reaction activities, the multiphase interfacial components of CuS (1 0 5), Fe0.5Ni0.5S2 (2 1 0), and CuFe2S3 (2 0 0) are constructed to enhance the interfacial polarization loss in multielement Cu‐based sulfides. Compared with single‐phase high‐entropy Zn‐based sulfides (ZnFeCoNiCr‐S), the multiphase Cu‐based sulfides (CuFeCoNiCr‐S) possess optimized EMW absorption properties (effective absorption bandwidth (EAB) of 6.70 GHz at 2.00 mm) due to the existence of specific interface of CuS (1 0 5)/CuFe2S3 (2 0 0) with proper EM parameters. Furthermore, single‐phase ZnFeCoNiCr‐S into FeNi2S4 (3 1 1)/(Zn, Fe)S (1 1 1) heterointerface through 400 °C heat‐treated is decomposed. The EMW absorption properties are enhanced by strong interfacial polarization (EAB of 4.83 GHz at 1.45 mm). This work reveals the reasons for the limited EMW absorption properties of high‐entropy sulfides and proposes multiphase interface engineering to improve charge accumulation and polarization between specific interfaces, leading to the enhanced EMW absorption properties. [ABSTRACT FROM AUTHOR]

The current research describes the successful fabrication and characterization of ternary metal sulphide thin film, NiS:Cu2S:Nd2S3, by physical vapour deposition with diethyldithiocarbamate as the sulphur source. Various analytical approaches were used to evaluate the synthetic material's crystallographic, morphological, and optical properties. The ternary metal sulphide thin films possessed a crystallite size of 33.5 nm, whilst SEM imaging revealed the presence of geometrical form with tiny clustered bodies. Furthermore, XPS examination showed the existence of Nd 4d, Cu 2p, Ni 2p, and S 2p core-level peaks in the ternary metal sulphide thin films. The current study revealed that the synthesized material had a band gap energy of 3.5 eV. The material's electrochemical properties were evaluated using cyclic voltammetry, which revealed good supercapacitance performance with a specific capacitance of 412 Fg−1. The cycle stability of the nanoparticle thin films was also found to be good, highlighting its potential as an energy storage medium. Furthermore, the photocatalytic activity of the synthesized material was investigated, especially its capacity to breakdown a variety of contaminants such as malachite green dye, fluopyram, and phenol with a highest degradation rate constant 1.6 × 10−2 min−1. These findings provide compelling evidence of the potential of ternary metal sulphide thin films for a wide range of technological applications, including but not limited to energy storage and photocatalysis. [ABSTRACT FROM AUTHOR]

We report the synthesis of lead(II) complexes of 2-(thiophen-2-ylmethylene) hydrazine-1-carbothioamide (1) and 2-(1-(thiophen-2-yl) ethylene) hydrazine-1-carbothioamide (2), which were used as single source precursors in hexadecylamine (HDA) and oleylamine (OLA) at 190, 230, and 270°C to synthesize lead(II) sulfide nanoparticles. Optical studies by UV–vis analysis showed a general blue shift in the absorption band edge of the PbS nanoparticles (NPs) with energy bandgaps determined by Tauc's plots ranging from 2.15 to 3.11 eV. The development of NPs with a variety of morphologies that changed with temperature and precursor type was demonstrated by morphological characterization using scanning electron microscopy and transmission electron microscopy. Cubic, rod-shaped, and nearly spherical-shaped PbS were formed. Powder X-ray diffraction (p-XRD) structural studies revealed the face-centered cubic structure of PbS nanoparticles. The elements contained in the nanoparticles were identified by energy dispersive X-ray spectroscopy (EDX). These results suggest that the size, shape, and optical properties of the synthesized PbS NPs were affected by reaction temperature, capping group, and precursor type. Under UV irradiation, the photocatalytic activity of HDA-capped PbS nanoparticles on the degradation of methylene blue dye ranged from 28.3% to 60.0%, with lead sulfide nanoparticle obtained by thermolysis of complex (1) at 230°C showing the highest photocatalytic efficiency (60.0%). [ABSTRACT FROM AUTHOR]

Platinum and Pd-arsenides, antimonides, tellurides, bismuthinides, and sulfides are the major hosts of Pt and Pd in magmatic and hydrothermal Cu-Ni-sulfide ores. Textural relationships among such minerals in nature often provide contradictory messages about the mechanism and timing of their formation. To know how and when Pt and Pd mineral phases crystallize from sulfide- saturated liquids and how their compositions and textures evolve during cooling, we undertook controlled cooling experiments in evacuated silica tubes. A Cu-Ni-Fe sulfide mixture, similar in composition to the average Merensky Reef sulfide magma, was charged (in a 9:1wt.% proportion) with one of the PtAs2, PtTe2, PtSb2, PtBi2, PdAs2, PdTe2, PdSb, and PdBi2 compounds, heated to 1,100°C, and slowly cooled (15°C/day) to room temperature. The run products were sampled at 950°C, 750°C, and 25°C by quenching the silica tubes in water. The results show that Pt formed stable phases with As, Te, and Sb above 950°C and with Bi and S below 750°C. The Pt phases were found mostly in the decomposed intermediate solid solution (ISS), and all the phases survived to 25°C with no compositional changes. At 950°C, Pd formed arsenide, telluride, and antimonide immiscible melts that coexisted with monosulfide solid solution (MSS) and sulfide melt. The composition of the Pd- semimetal melt droplets changed during cooling by equilibration with the host sulfide. Palladium mineral phases formed at temperatures below 750°C directly from the immiscible semimetal-rich melts where they kept the rounded shapes of the melt droplets. Ni-sulfarsenides preceded the formation of Pd arsenides. No Ni tellurides, antimonides, or bismuthinides formed in any of the systems, implying that their formation requires higher semimetal/Pt + Pd ratios. The decomposition of MSS and ISS to base metal sulfides led to significant textural changes in Pt and Pd mineral grains. The compositions of Pt and Pd phases are inherited from the magmatic stage, and their textures are low-temperature (<450°C) features. [ABSTRACT FROM AUTHOR]

Lead sulfide (PbS) colloidal quantum dot (CQD) photodiodes integrated with silicon‐based readout integrated circuits (ROICs) offer a promising solution for the next‐generation short‐wave infrared (SWIR) imaging technology. Despite their potential, large‐size CQD photodiodes pose a challenge due to high dark currents resulting from surface states on non‐passivated (100) facets and trap states generated by CQD fusion. In this work, we present a novel approach to address this issue by introducing double‐ended ligands that supplementally passivate (100) facets of halide‐capped large‐size CQDs, leading to suppressed bandtail states and reduced defect concentration. Our results demonstrate that the dark current density is highly suppressed by about an order of magnitude to 9.6 nA cm−2 at −10 mV, which is among the lowest reported for PbS CQD photodiodes. Furthermore, the performance of the photodiodes is exemplary, yielding an external quantum efficiency of 50.8% (which corresponds to a responsivity of 0.532 A W−1) and a specific detectivity of 2.5 × 1012 Jones at 1300 nm. By integrating CQD photodiodes with CMOS ROICs, the CQD imager provides high‐resolution (640 × 512) SWIR imaging for infrared penetration and material discrimination. [ABSTRACT FROM AUTHOR]

Microcrystalline lead sulfide (PbS) films were synthesized using the chemical deposition method. The films were deposited on pre-cleaned glass substrates and polished silicon wafers. Chemicals of high purity were utilized in the process. The morphology, composition, and structure of the films were characterized using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD). The films exhibited a galena phase with a face-centered cubic structure belonging to the Fm-3m space group. The average grain size was determined using the Williamson-Hall method, revealing a homogenous structure. Raman spectroscopy further confirmed the structural integrity of the films. The obtained results contribute to the understanding of the synthesis and properties of microcrystalline PbS films. [ABSTRACT FROM AUTHOR]

Copyright of Journal of University of Anbar for Pure Science is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Colloidal semiconductor nanoparticles (NPs) represent an emergent state of matter with unique properties, bridging bulk materials and molecular structures. Their distinct physical attributes, such as bandgap and photoluminescence, are intricately tied to their size and morphology. Ligand passivation plays a crucial role in shaping NPs and determining their physical properties. Ligand exchange (LE) offers a versatile approach to tailoring NP properties, often guided by Pearson’s Hard–Soft Acid–Base theory. Lead sulfide (PbS), a semiconductor of considerable interest, exhibits size-dependent tunable bandgaps from the infrared to the visible range. Here, we present two methods for synthesizing water-soluble, polyvinylpyrrolidone (PVP)-coated PbS NPs. The first involves direct synthesis in an aqueous solution while utilizing PVP as the surfactant for the formation of nano-cubes with a crystal coherence length of ~30 nm, while the second involves LE from octadecylamine-coated PbS truncated nano-cubes to PVP-coated PbS NPs with a crystal coherence length of ~15 nm. Multiple characterization techniques, including X-ray diffraction, transmission electron microscopy, Fourier-transform infrared spectroscopy, and thermal gravimetric analysis, confirmed the results of the synthesis and allowed us to monitor the ligand exchange process. Our findings demonstrate efficient and environmentally friendly approaches for synthesizing PVP-coated PbS NPs.

In this study, a sol-gel film based on lead sulfide (PbS) quantum dots incorporated into a host network was synthesized as a special nanostructured composite material with potential applications in temperature sensor systems. This work dealt with the optical, structural, and morphological properties of a representative PbS quantum dot (QD)-containing thin film belonging to the Al2O3–SiO2–P2O5 system. The film was prepared using the sol-gel method combined with the spin coating technique, starting from a precursor solution containing a suspension of PbS QDs in toluene with a narrow size distribution and coated on a glass substrate in a multilayer process, followed by annealing of each deposited layer. The size (approximately 10 nm) of the lead sulfide nanocrystallites was validated by XRD and by the quantum confinement effect based on the band gap value and by TEM results. The photoluminescence peak of 1505 nm was very close to that of the precursor PbS QD solution, which demonstrated that the synthesis route of the film preserved the optical emission characteristic of the PbS QDs. The photoluminescence of the lead sulfide QD-containing film in the near infrared domain demonstrates that this material is a promising candidate for future sensing applications in temperature monitoring. [ABSTRACT FROM AUTHOR]

Owing to their capability to disrupt the oxidative protein folding environment in the endoplasmic reticulum (ER), thiol antioxidants, such as dithiothreitol (DTT), are used as ER‐specific stressors. We recently showed that thiol antioxidants modulate the methionine‐homocysteine cycle by upregulating an S‐adenosylmethionine‐dependent methyltransferase, rips‐1, in Caenorhabditis elegans. However, the changes in cellular physiology induced by thiol stress that modulate the methionine‐homocysteine cycle remain uncharacterized. Here, using forward genetic screens in C. elegans, we discover that thiol stress enhances rips‐1 expression via the hypoxia response pathway. We demonstrate that thiol stress activates the hypoxia response pathway. The activation of the hypoxia response pathway by thiol stress is conserved in human cells. The hypoxia response pathway enhances thiol toxicity via rips‐1 expression and confers protection against thiol toxicity via rips‐1‐independent mechanisms. Finally, we show that DTT might activate the hypoxia response pathway by producing hydrogen sulfide. Our studies reveal an intriguing interaction between thiol‐mediated reductive stress and the hypoxia response pathway and challenge the current model that thiol antioxidant DTT disrupts only the ER milieu in the cell. Synopsis: Thiol antioxidant dithiothreitol (DTT) is used as an endoplasmic reticulum (ER)‐specific stressor; however, its physiological effects beyond the ER remain obscurely defined. This study demonstrates that DTT activates the hypoxia response pathway in Caenorhabditis elegans and human cells. Genetic screens in C. elegans identify that thiol reductive stress by DTT activates the hypoxia response pathway.DTT pretreatment protects C. elegans against cyanide‐mediated killing on Pseudomonas aeruginosa.The hypoxia response pathway has opposing roles in regulating thiol toxicity.DTT exposure leads to hydrogen sulfide production. [ABSTRACT FROM AUTHOR]

This study focuses on the preparation of a high-performance visible light photodetector using nanocrystalline lead sulphide (PbS) thin films. The thin films were deposited onto glass substrates via the chemical bath deposition technique, utilizing an aqueous solution of lead acetate and thiourea. The structural study carried out on the deposited films by X-ray diffraction exhibited a cubic crystal structure with a PbS phase. The optical characteristics of PbS thin films were investigated employing UV-Vis absorption spectroscopy. The absorption spectroscopy was carried out in the wavelength range of 400–1000 nm. The absorbance spectra were utilized to calculate the spectral dependence of several optical parameters: band gap, refractive index, extinction coefficient, dielectric constant, and optical and electrical conductivity. The photocurrent was measured in nanocrystalline PbS thin films under the illumination of specific LED wavelength sources. The quality of the PbS thin film as a photodetector was investigated by determining the rise time, decay time, photosensitivity, specific detectivity, and external quantum efficiency. [ABSTRACT FROM AUTHOR]

One of the emerging paradigms to resolve pressing issues of modern computing electronics, such as limits in miniaturization and excessive energy consumption, takes inspiration from the biological brain and is therefore expected to display some of its properties, such as energy efficiency and effective learning. Moreover, one of the brain's remarkable properties is its ability to process complex information by resolving it on different timescales. In synapse‐emulating artificial devices, some form of memory (e.g., hysteresis in current–voltage characteristics) is required. One of the important characteristics of biological synapses is the coexistence of short‐ and long‐term memory, also called plasticity. However, a broader exploration of memory at multiple timescales in materials remains limited. Herein, the first example of synaptic transistors utilizing colloidal quantum dots (CQDs) as active material is reported. It is demonstrated that PbS‐CQDs, with metal halide and perovskite‐like ligands, are ideal as an active material for synaptic transistors exhibiting both short‐ and long‐term plasticity. Most interestingly, by changing the chemistry of the quantum dot outer monolayer, a drastic change in the temporal response of the learning is observed, demonstrating the possibility of engineering materials exhibiting learning at multiple timescales, similar to the biological synapses. [ABSTRACT FROM AUTHOR]

The effects of copper concentration on the properties of copper lead sulfide (CuxPb1-sS) thin films have been reported. Chemical bath deposition (CBD) method was used to deposit the ternary material on soda-lime substrates. Here, the CuxPb1-xS films were grown using copper(II) chloride, lead nitrate, and thiourea as sources of copper (Cu), lead (Pb) and sulfur (S), respectively. The grown films were examined using X-ray diffractometer (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDX) spectroscopy, UV-spectrophotometer and four-point (4P) probes. XRD measurements revealed a polycrystalline material with strong adherent to the substrates. SEM readings indicated various grain-like crystalline morphologies with different sizes that change with copper concentrations. The EDX studies revealed that the deposited material consist of copper, lead and sulfur in various compositions. The transmittance was high in the near infrared regions of the electromagnetic radiation and, also decreases with copper concentrations. The band gap (Eg) varies from 2.05 to 2.50 eV with increase in copper concentrations. The study shows that CBD is an excellent method in depositing good quality films for device applications. [ABSTRACT FROM AUTHOR]

In this paper, we discuss general trends in the IR luminescence of colloidal PbS quantum dots 3 nm in average size, capped with thioglycolic acid molecules (PbS/TGA QDs). Treatment of the PbS/TGA QDs with a KI solution has been shown to cause a shift of a composite luminescence band peaking at 1120 nm to shorter wavelengths, to 1060 nm; an increase in the quantum yield of its shorter wavelength component, related to excitonic emission, from 1 to 10%; and quenching of its longer wavelength component, due to radiative recombination at defect levels. In this process, the cubic structure of PbS undergoes no changes. The average size of the PbS/TGA QDs has been shown to decrease slightly, by 0.2–0.3 nm. The conclusion has been drawn that the increase in the quantum yield of excitonic emission from the PbS/TGA QDs as a result of KI treatment is due to the more efficient passivation of interfacial defects, which act as both recombination luminescence and nonradiative carrier recombination channels. Using thermoluminescence in the temperature range from 80 to 350 K, we have demonstrated the presence of two types of shallow localized states, at 0.17- and 0.25-eV depths, whose density is only slightly sensitive to treatment of the PbS/TGA QDs with a KI solution. We assume that some of the traps identified are due to native defects in the nanocrystals—interstitial lead and sulfur ions—rather than to dangling bonds of surface lead and sulfur atoms. [ABSTRACT FROM AUTHOR]

Strengthening practical training and cultivating innovative awareness are indispensable components of higher engineering education, and experimental teaching is needed in the process of cultivating innovative thinking awareness. Considering the high requirements of both theoretical and practical aspects in the major of optoelectronic information science and engineering, as well as the fast updating speed of theoretical knowledge, an experimental teaching platform for ultrafast fiber laser manufacturing technology is designed in this study. The influence of saturable absorbers based on lead sulfide quantum dots on the core performance parameters of ultrafast fiber lasers is deeply studied. This comprehensive experiment covers various aspects such as material preparation and characterization, development of saturable absorbers, construction and testing of ultrafast laser systems, etc. The experimental content is progressive and comprehensive, which enables learners to flexibly grasp various knowledge points and enhance their engineering practice and innovation abilities. [ABSTRACT FROM AUTHOR]

The Július metamorphosed manganese occurrence is situated near the Betliar village in the Spišsko-gemerské rudohorie Mts. (Western Carpathians). Mineralization occurs in the form of manganese carbonate-silicate lenticular body hosted in Lower Paleozoic metasedimentary and metavolcanoclastic rocks of the Bystrý potok Formation, Gelnica Group, Gemeric Unit. The Mn mineralization dominantly consists of rhodochrosite, pyroxmangite, spessartine, magnetite, clino-suenoite, clino-ferro-suenoite, tephroite, pyrophanite and pyrosmalite-(Mn) alongside with pyrite, pyrrhotite, galena, sphalerite, cobaltite, gersdorffite, siegenite, violarite and minor pentlandite and millerite. Very rare minerals, such as hejtmanite, bafertisite as well as a two recently approved members of the epidote supergroup [ferriandrosite-(Ce) and vielleaureite-(Ce)] were also identified. Significant feature of studied mineralization in comparison with the other occurrences of metamorphosed manganese mineralization in the Spišsko-gemerské rudohorie Mts. is the absence of rhodonite. Mineralization at the Július occurrence originates from heterogenous sediment with occurrence of manganiferous, calcareous, argillaceous and terrigenous material with quartz and Ba-rich minerals locally incorporated by material from a volcanic source. Based on mineralogy and ore textures, two metamorphic stages affecting the final mineral composition of Mn mineralization can be distinguished. Generally, the mineral assemblage was likely formed during the Variscan metamorphic stage in the p-T conditions approximately 420-450 °C and pressure 2-4 kbar, as a peak of a metamorphism can be considered the high-grade greenschist facies conditions. Alpine metamorphic phase determined the appearance of veins and veinlets composed of rhodochrosite-chamosite-quartz, pyroxmangite and spessartine. In agreement with lowering temperature of metamorphism and with higher mobility of REE, minerals such as epidotes, baryte and pyrosmalite-(Mn) were formed. Hydrothermal activity led to the formation of sulphides with slightly increased content of Mn. Final stage of metamorphic evolution was influenced by local metasomatic processes. [ABSTRACT FROM AUTHOR]

Ag8SnS6 (ATS) has been reported to have a band gap of 1.33 eV and is expected to be a suitable material for the light-absorbing layers of compound thin-film solar cells. However, studies on solar cells that use ATS are currently lacking. The objective of this study is to obtain high-quality ATS thin films for the realization of compound thin-film solar cells using vacuum deposition and sulfide annealing. First, glass/SnS/Ag stacked precursors are prepared by vacuum deposition. Subsequently, they are converted to the ATS phase via sulfide annealing, and various process conditions, namely, annealing time, annealing temperature, and number of steps, are studied. By setting the heat treatment temperature at 550 °C and the heat treatment time at 60 min, a high-quality ATS thin film could be obtained. Multi-step heat treatment also produces thin films with nearly no segregation or voids. [ABSTRACT FROM AUTHOR]

Heavy metals in a polluted environment are toxic to life. However, some microorganisms can remove or immobilize heavy metals through biomineralization. These bacteria also form minerals with compositions similar to those of semiconductors. Here, this bioprocess was used to fabricate semiconductors with low energy consumption and cost. Bacteria that form lead sulfide (PbS) nanoparticles were screened, and the crystallinity and semiconductor properties of the resulting nanoparticles were characterized. Bacterial consortia that formed PbS nanoparticles were obtained. Extracellular particle size ranged from 3.9 to 5.5 nm, and lattice fringes were observed. The lattice fringes and electron diffraction spectra corresponded to crystalline PbS. The X-ray diffraction (XRD) patterns of bacterial PbS exhibited clear diffraction peaks. The experimental and theoretical data of the diffraction angles on each crystal plane of polycrystalline PbS were in good agreement. Synchrotron XRD measurements showed no crystalline impurity-derived peaks. Thus, bacterial biomineralization can form ultrafine crystalline PbS nanoparticles. Optical absorption and current–voltage measurements of PbS were obtained to characterize the semiconductor properties; the results showed semiconductor quantum dot behavior. Moreover, the current increased under light irradiation when PbS nanoparticles were used. These results suggest that biogenic PbS has band gaps and exhibits the general fundamental characteristics of a semiconductor. [ABSTRACT FROM AUTHOR]

A quantum dot (QD) thin film of arsenic (III) oxide-hydroxide/polypyrrole (As2S3-As2O3/Ppy) with a supernova-like shape has been developed for optoelectronic applications across a wide optical range, spanning from ultraviolet (UV) to infrared (IR). The fabrication process involves the polymerization of pyrrole to form Ppy in the presence of NaAsO2 and K2S2O8. The resulting QD exhibits a remarkable morphology characterized by a supernova-like structure and a porous nature with a particle size of 4 nm. The unique morphology of the QD contributes to its optical properties. The material demonstrates a maximum optical absorbance that extends up to 600 nm. The chemical structure of the composite has been proved using various characterization techniques. The As2S3-As2O3/Ppy QD thin film holds significant potential for optoelectronic applications, particularly in light detection across multiple optical regions. Its sensitivity has been evaluated through the measurement of photoresponsivity (R), yielding a high value of 0.31 mA/W. This indicates a substantial current density (Jph) of 0.031 mA/cm2 at a wavelength of 340 nm. Additionally, the detectivity (D) of the photodetector has been calculated based on these values, resulting in a detection capability of 6.9 × 107 Jones. This indicates the ability to detect low levels of photons using this photodetector. The highly reproducible nature of this photodetector enables its application in various optoelectronic systems. The As2S3-As2O3/Ppy QD thin film offers great promise as a versatile optoelectronic application with its wide optical range, excellent sensitivity, and detectivity. [ABSTRACT FROM AUTHOR]

[Display omitted] • Eco-friendly millimeter-grade SA/PAAS/PAC (SPP) hydrogel beads were synthesized from simple cationic cross-linking. • SPP beads showed effective adsorption capacity towards Pb(II). • In-situ vulcanization was applied to reuse Pb(II) as photocatalyst. • Excellent photocatalytic degradation of Rhodamine-B (RhB) was obtained, compared to other conventional photocatalysts. In this study, sodium alginate (SA), sodium polyacrylate (PAAS) and powdered activated carbon (PAC) were cross-linked by calcium ions [(Ca(II)] to form SA/PAAS/PAC (SPP) hydrogel beads. The hydrogel-lead sulfide (SPP-PbS) nanocomposites were successfully synthesized by in-situ vulcanization after the lead ions [(Pb(II)] adsorption. SPP showed an optimal swelling ratio (600% at the pH value of 5.0) and superior thermal stability (206 °C of heat-resistance index). The adsorption data of Pb(II) was compatible with the Langmuir model, and the maximum adsorption capacity of SPP was 391.65 mg/g after optimizing the mass ratio of SA to PAAS (3:1). The addition of PAC not only enhanced the adsorption capacity and stability, but also promoted photodegradation. The significant dispersive capacity of PAC and PAAS resulted in PbS nanoparticles with particle sizes of around 20 nm. SPP-PbS showed good photocatalysis and reusability. The degradation rate of RhB (200 mL, 10 mg/L) was 94% within 2 h and maintained above 80% after 5 cycles. The treatment efficiency of SPP was more than 80% in actual surface water. The results of quenching experiments and electron spin resonance (ESR) experiments revealed that the superoxide radicals (O 2 –) and holes (h+) were the main active species in the photocatalytic process. [ABSTRACT FROM AUTHOR]

Copper sulfide nanoparticles have a wide range of applications in various fields, and improving their physical properties is highly desirable. In this study, we investigate the influence of nickel concentrations on the structural, optical, and magnetic characteristics of CuS nanoparticles. The structural properties of Cu1-xNixS (x = 0.00, 0.02, 0.04, 0.06, 0.08, and 0.10) were demonstrated using X-ray diffraction (XRD), which confirmed that all samples have a single hexagonal phase. The Energy Dispersive X-ray Technique (EDAX) was used to investigate the elemental analysis of Cu1-xNixS. The XPS study revealed the valence states of Cu, Ni, and S in the Cu0.94Ni0.06S nanoparticles, as well as surface oxidation. The optical characteristics were calculated based on the absorbance optical spectra of the films using a UV-vis-NIR double-beam spectrophotometer in the wavelength range of 400-1000 nm. The optical band gap for CuS and Ni-doped CuS samples decreases as the Ni concentration rises. Magnetic studies (using the M-H curve) demonstrate that 2% and 4% Ni-doped CuS nanoparticles exhibit strong ferromagnetism at ambient temperature and transition to a paramagnetic nature. These results suggest the potential of creating spintronic devices using Ni-doped CuS nanoparticles. [ABSTRACT FROM AUTHOR]

In this study, iron sulphide thin films were prepared by simple and low-cost chemical spray-pyrolysis method using tilt deposition with a spraying angle of 45° and substrates temperature of 200°C. The precursors were iron chloride salt (FeCl3) and thiourea. After the preparation process, some of the samples are annealed at a temperature 400°C for 30 min. It was found that the as-deposited iron sulphide thin films (without annealing) had an amorphous structure, which gave higher absorption coefficient (2 × 105 cm−1) for thin film thickness 400 nm. This study also presents a novel method to obtain polycrystalline FeS2 thin films with pyrite phase and optimum energy bandgap and high absorption coefficient. A thin film of iron sulphide was also deposited on fluorine-doped tin oxide glass to work as a counter electrode for dye-sensitized solar cells. [ABSTRACT FROM AUTHOR]

The possibility of obtaining nanocrystaline lead sulfide by an electrolytic method using lead electrodes is demonstrated, and the influence of temperature on the synthesis process is investigated. Based on the results of X-ray diffraction studies, the chemical and phase composition of the obtained samples is determined, as well as the parameters of the unit cell of the crystals lattice. The size of the nanocrystallites and the magnitude of residual mechanical strain in them is determined using the methods of Debye-Scherrer and Williamson-Hall. The results of X-ray diffraction are in agreement with the results of the Raman scattering on phonons.

One of the emerging paradigms to resolve pressing issues of modern computing electronics, such as limits in miniaturization and excessive energy consumption, takes inspiration from the biological brain and is therefore expected to display some of its properties, such as energy efficiency and effective learning. Moreover, one of the brain's remarkable properties is its ability to process complex information by resolving it on different timescales. In synapse‐emulating artificial devices, some form of memory (e.g., hysteresis in current–voltage characteristics) is required. One of the important characteristics of biological synapses is the coexistence of short‐ and long‐term memory, also called plasticity. However, a broader exploration of memory at multiple timescales in materials remains limited. Herein, the first example of synaptic transistors utilizing colloidal quantum dots (CQDs) as active material is reported. It is demonstrated that PbS‐CQDs, with metal halide and perovskite‐like ligands, are ideal as an active material for synaptic transistors exhibiting both short‐ and long‐term plasticity. Most interestingly, by changing the chemistry of the quantum dot outer monolayer, a drastic change in the temporal response of the learning is observed, demonstrating the possibility of engineering materials exhibiting learning at multiple timescales, similar to the biological synapses.

The spin-coating method has been employed for nanostructured crystalline zinc oxide (ZnO) thin film preparation on FTO glass substrates. Cadmium sulfide (CdS) layers were then deposited on the surface via the chemical bath deposition method. To investigate the effect of the formation of the CdS layer on ZnO/FTO, the deposition of these layers was performed at three different temperatures (40, 60, and 80 °C). The synthesized CdS/ZnO composite was found to have homogenously distributed crystalline grains of both ZnO and CdS. The uniform distribution of the grains and the equal molar ratio of the two components resulted in excellent optical and photocatalytic performance. Analysis of CdS/ZnO thin films was performed using XRD analysis, UV-vis spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and linear sweep voltammetry. The best optical, morphological, and electrical properties and the highest photocurrent value of the CdS/ZnO thin films were obtained when the CdS layers were formed at 60 °C. X-ray diffraction characterization revealed that CdS/ZnO thin films crystallized into hexagonal wurtzite ZnO and cubic CdS. The crystallite size of ZnO and CdS/ZnO was ~38 nm and ~19 nm, respectively. The band gap calculated for CdS/ZnO, formed at different temperatures, varies from 2.05 to 2.15 eV. [ABSTRACT FROM AUTHOR]

Colloidal quantum dots (CQDs) solar cells are less efficient because of the carrier recombination within the material. The electron and hole transport layers have high impact on the performance of CQDs based solar cells which makes its investigation a very important component of the development of the more efficient devices. In this work, we have tried performance optimization in tetrabutyl ammonium iodide capped lead sulfide (PbS) CQDs (PbS-TBAI) as absorber layers based solar cells by incorporating different hole transport layers (HTLs) to achieve better power conversion efficiency (PCE) in different device architectures by SCAPS—1D numerical simulation software. It was observed from the simulation that the ITO/TiO2/PbS-TBAI/HTL/Au device architecture shows higher power conversion efficiency as compared to the conventional experimentally realized device architecture of ITO/TiO2/PbS-TBAI/PbS-EDT/HTL/Au. The influence of interface defect density (IDD) at the interface TiO2/PbS-TBAI has also been studied where IDD is varied from 1 × 1013 cm−2 to 1 × 1018 cm−2 while keeping the rest of the device parameters intact. The result shows a noteworthy reduction in the PV performance of the device at higher IDD. This modelled device structure provides a new direction toward the experimental realization in high efficiency PbS QDs solar cells. [ABSTRACT FROM AUTHOR]