Pb Sn Research Articles

Implications of Nd isotopic mapping for crustal composition and metallogenesis in the Sanjiang orogenic belt (SW China)

The Sanjiang orogenic belt, located in southwestern China and the southeastern Tibetan Plateau, includes a variety of economically important metal deposits. Previous studies have focused on Lu-Hf isotopic mapping to suggest its lithospheric architecture and mineralization. In this study, we provide the results of Nd isotopic mapping and compare them with the results of Hf isotopic mapping based on the similarity of Sm-Nd and Lu-Hf isotope systems, which indicate three juvenile domains with high εNd(t) and young Nd model ages within the Eastern Qiangtang-Simao terrane, while presenting negative εNd(t) values over the entire horizon. The very negative εNd(t) and old Nd model ages found in the Tengchong-Baoshan terrane and Changning-Menglian suture suggest that these terranes are old and might be reworked. The Nd isotopic mapping of the Sanjiang orogenic belt also suggests a relationship between different lithospheric architectures and the locations of distinct ore deposits. Porphyry-skarn Cu–Mo–(Au) deposits occur in the juvenile crust, which has relatively high εNd(t) (−3.3–5.1) and young TDM ages, whereas skarn and hydrothermal vein-type W–Sn deposits and Pb‒Zn‒Cu‒Ag deposits are located in the low-εNd(t) area.

Mapping of geological complexity and analyzing its relationship with the distribution of gold deposits in the Guangxi Gold Ore Province, Southern China

The Guangxi gold ore province contains >370 gold deposits with total resources of >260 t Au. Factor analysis (FA) of geochemical data, and calculation of lineament density within 10 km, 20 km, and 30 km circular search grids across a geological map, were applied in Guangxi to highlight geological complexity and to analyze its relationships with the distribution of gold deposits. The FA of stream sediment geochemical data for 42 elements, subjected first to center logarithmic transformation (clr), yield several element combinations that allowed distinction of metallogenic signatures from geological backgrounds. The element combinations of the first and second factors were Cd–Co–Cr–Cu–Li–Mn–Ni–P–Sb–Y–Zn–Mg and Be–Bi–La–Nb–Pb–Sn–Th–U–W–Zr–Al, and the spatial distributions of their factor scores overlap the Devonian to Permian strata and granite, respectively. The distribution of factor scores of mineralization-related element combination, Ag–As–Au–Mo, coincides with 70 % of gold deposits. The lineament density mapping can highlight different-scale faults and lithological contacts by using circular search grids with different diameters. The C–A fractal modeling for lineament density has indicated four populations, namely low, moderate-low, moderate-high, and high lineament densities. About ∼80 to ∼90 % of the known gold deposits exist in areas with moderate-low to moderate-high lineament densities. This highlights the importance of distinguishing geological complexity based on faults and lithological contacts, which are commonly the pathways for the focused fluid flow and gold ore formation. The deposit-scale geological complexity mapping has predicted several exploration targets, where high-grade gold orebodies have been prospected successfully by drilling in 2018. The geological complexity mapping is a kind of geochemical and geological complementation for resource potential assessment.

Role of Cu percentage in the Sn-xCu alloy on the mechanical performance at Sn-xCu/ENIG interface produced by laser soldering

PurposePb-free solders have been developed to replace the standard Sn–Pb eutectic solder since the prohibition on Pb used in solders. The Sn–Ag–Cu series of lead-free solders is the most extensively used in the electronics industry. The Ag3Sn, which forms during isothermal ageing, can significantly degrade solder joint reliability. Sn–Ag–Cu solder’s high price further hindered its use in the electronics industry. This paper aims to investigate different copper percentages into Sn–xCu solder alloy to improve its microstructure and strength performance.Design/methodology/approachThe solder alloys used in this work were Sn–xCu, where x = 0.0, 0.3, 0.5, 0.7, 1.0 Wt.%, which was soldered onto electroless nickel immersion gold (ENIG) substrate using carbon dioxide (CO2) gas laser. Then these samples were subjected to isothermal aging for 0, 200, 500, 1,000 and 2,000 h. The Sn–xCu solder alloy was fabricated through a powder metallurgy process.FindingsMicrostructure characterization showed that Cu addition resulted in fine and rounded shape of Cu–Sn–Ni particles. Shear strength of Sn–xCu solder joints was increased with increasing Cu content, but at aging duration of 1,000 h, it dropped slightly. It is believed that the strength improved due to the increment of diffusion rate during isothermal aging.Practical implicationsIn a Cu–Sn solder, the recommended amount is 1.0 Wt.% of Cu. In extensive aging procedures, it was discovered that Sn1.0Cu solder improved the reliability of solder joints. The findings indicated that the innovative solder alloys might satisfy the needs of high-reliability applications.Originality/valueThe study shows that the right amount of Cu enhances the solidification of Sn–Cu solder, increasing the shear force of the Cu–Sn solder joint. The Sn1.0Cu exhibits a ductile fracture on the top microstructure, improving the joint’s average shear strength.

Ruddlesden–Popper Perovskite Alloys: Continuous and Discontinuous Tuning of the Electronic Structure

Alloying mixed ratios of elements into the halide perovskite (HP) structure has proven to be an effective method of tuning these materials’ structural and electronic properties for photovoltaic and other optoelectronic applications. However, the standard spectroscopies used to characterize HP alloys such as absorption and photoluminescence are limited in their ability to detect disorder and phase segregation within the structure. Here, we characterize these properties in 2D HP alloys to a greater degree by using electroabsorption spectroscopy to study thin films with mixed-metal (Pb–Sn) and mixed-halide (Br–Cl and Br–I) compositions. The large spectral separation of band-edge states in 2D HPs allow us to detect a coexistence of elemental-rich domains within the Pb–Sn and Br–I alloys. Meanwhile, we find that the Br–Cl alloys exhibit sharper spectral features and a more uniform electroabsorption response indicative of an ordered structure, albeit still not as ordered as their pure Br and Cl counterparts. The band gap energies of the Br–Cl series (PEA2PbBrxCl4 – x) can be continuously tuned between 3.425 and 4.13 eV via the Br:Cl ratio, while the exciton binding energies can be tuned from 349 to 487 meV.

FA/Cs-based mixed Pb–Sn perovskite solar cells: A review of recent advances in stability and efficiency

Perovskite solar cells (PSCs) have gained widespread attention due to their impressive optoelectronic properties, extraordinarily high efficiency, and low-cost manufacturing processes. PSCs are poised to usher in a new era of clean energy production. However, the use of methylammonium (MA) as the A-site cation in PSCs may result in poor thermal and atmospheric stability, limiting their potential for widespread commercialization. On the other hand, the most extensively studied perovskite systems with respect to B-site cations are pure Pb-based compositions due to their high device performance demonstrated to date. However, mixed Pb–Sn compositions can offer optimal bandgap energies for single-junction solar cells, suggesting the promise of future efficiency improvements. Thus, this review focuses on mixed Pb–Sn perovskite solar cells that use formamidinium (FA) or mixed cations of FA and cesium (Cs) without MA. These materials have bandgap energies suitable for use in either single-junction or multi-junction solar cells and show improved stability compared to their MA-based counterparts. We discuss the structural and optoelectronic properties of FA/Cs-based Pb–Sn perovskites and the efforts to improve their solar cell performance and stability through additive engineering, process optimization, and structural modifications. Our review highlights the potential for FA/Cs-based mixed Pb–Sn perovskites as a more stable and efficient alternative for future commercial applications of PSCs.

Regression based computer vision analysis of volume-fraction effect on Pb–Sn solid–liquid coarsening in microgravity

Regression based computer vision analysis of volume-fraction effect on Pb–Sn solid–liquid coarsening in microgravity

The influence of melt composition, liquidus temperature and solidus temperature on vapour explosions in melt droplet impingement experiments

For the investigation of vapour explosions, droplet impingement experiments were performed with the binary system Pb–Sn and the pseudo-binary system PbS–Cu2S. The experiments were performed with a melt at 600 °C (Pb–Sn) or 700 °C (PbS–Cu2S) and a water bath at ambient temperature and pressure. A hydrophone and a high-speed camera were used to study the interaction and from this data, the explosion probability and intensity were determined.The explosion probability had a single minimum around 70 wt% Sn, close to the eutectic composition. Moreover, the explosion probability increased approximately linearly with changing composition towards the pure melts, and was similar for pure tin and pure lead. On the other hand, the explosion intensity was comparable for tin and the eutectic alloy while clearly lower for lead. Almost all intermediate alloys had a reduced explosion intensity.Based on the variation in composition, the effects of the liquidus or solidus temperature and the liquidus-solidus gap on the explosion behaviour were also investigated. The explosion probability in both systems increased with increasing liquidus temperature. Also, the maximum explosion intensity in the Pb–Sn system increased with increasing liquidus temperature. Both could be related to easier triggering due to (partial) solidification. On the other hand, the explosion intensity was found to decrease with increasing gap between liquidus and solidus temperature, as was also found in literature. No significant trends for the explosion intensity were found for experiments with PbS–Cu2S.

Mechanism of incipient annular corrosion of high-tin bronze in simulated soil solution

ABSTRACT The mechanism of Cu–Sn–Pb bronze (18.2 wt-% Sn) in a simulated soil solution was examined using optical microscopy, scanning electron microscopy, scanning Kelvin probe, X-ray photoelectron spectroscopy, X-ray diffraction and electrochemical techniques. The findings demonstrated that the α-phase possessed a more negative corrosion potential, and the central annular position was more active owing to the difference in the solid-solution tin content during casting. Cl− was not directly involved in the production of corrosive products in the early stage of corrosion, but it damaged the copper oxide layer and promoted the loss of copper ions. Subsequently, the tin oxide was gradually produced on the surface, and the selective copper dissolution led to abundant tin compounds on the surface.

Additive Engineering for Mixed Lead–Tin Narrow-Band-Gap Perovskite Solar Cells: Recent Advances and Perspectives

Low-cost perovskite solar cells (PSCs) with high power conversion efficiencies (PCEs) of >25% are considered as the most promising replacement for commercial silicon-based solar cells to realize a sustainable future. To break the theoretical PCE limits of single-junction PSCs, all-perovskite tandem solar cells consisting of a narrow-band-gap bottom subcell and a wide-band-gap top subcell have attracted particular attention recently. Mixed Pb–Sn perovskites with narrow band gaps have received great attention as an efficient light harvester in the bottom subcell of all-perovskite tandem solar cells as a result of the reduced toxicity, high light-absorbing capability, and matched current with the wide-band-gap top subcells. However, mixed Pb–Sn narrow-band-gap PSCs suffer from low PCEs, inferior stability, and high open-circuit voltage (Voc) loss, owing to the high defect amount and inferior perovskite film quality induced by the detrimental oxidation of Sn2+ cations and the rapid crystallization of perovskite crystals. Herein, the recent advances about the additive engineering for mixed Pb–Sn narrow-band-gap PSCs are reviewed by demonstrating the origins and unique features of Pb–Sn narrow-band-gap perovskites. Additionally, several strategies to improve PCEs and durability of Pb–Sn narrow-band-gap PSCs through additive engineering are proposed, including Sn2+ cation stabilization, heterojunction construction, crystallization control, surface/grain boundary passivation, film morphology control, carrier dynamics modulation, and gradient-distributed film formation. Furthermore, the existing challenges and future directions are also presented, aiming to provide important insights for designing and developing efficient and stable single-junction narrow-band-gap PSCs and all-perovskite tandem solar cells.

Constructing of Pb–Sn/α-PbO2/β-PbO2-Co2MnO4 composite electrode for enhanced oxygen evolution and zinc electrowinning

Developing a highly efficient and stable electrode for oxygen evolution reaction (OER) in harsh conditions (∼1.63 M H2SO4) is desirable but still challenging. Herein, the paper describes Co2MnO4 modifying β-PbO2 (Pb–Sn/α-PbO2/β-PbO2-Co2MnO4) via thermal decomposition and subsequent electrodeposition. Consequently, the synthesized electrode presents a layer structure, where Pb–Sn alloy serves as the matrix, α-PbO2 functions as mid-layer to enhance the binding force between the matrix and β-PbO2, and β-PbO2-Co2MnO4 acts as active layer for OER. In addition, the obtained quasi–three–dimensional Pb–Sn/α-PbO2/β-PbO2-Co2MnO4 electrode exhibits the lowest overpotential of 571 mV for 50 mA cm−2 and a small Tafel slope of 207.1 mV dec−1 in 1.63 M H2SO4 electrolyte. Moreover, it shows the smallest corrosion rate of 0.13 mg cm−2 h−1 and the longest accelerated service life of 59 h at 2 A cm−2. Furthermore, it is used as an anode for zinc electrowinning, in which the cell voltage and power consumption for producing one–ton zinc are lower by 230 mV and 304.2 kW h as compared with the benchmark electrode of Pb-0.76%Ag alloy. Hence, this paper provides the strategy to design and construct non-precious, high–performance catalysts for electrolysis and other applications.

High performance flexible Sn-Pb mixed perovskite solar cells enabled by a crosslinking additive

Flexible perovskite solar cells (PSCs) have drawn increasing attention due to their promising applications for wearable electronics and aerospace applications. However, the efficiency and stability of flexible PSCs still lag behind their rigid counterparts. Here, we use N,N-dimethyl acrylamide (DMAA) to in situ synthesize cross-linking polymer for flexible Sn–Pb mixed PSCs. DMAA can gather at grain boundary as a scaffold to regulate the crystallization of perovskite and reduce defects. The rigid and flexible Sn–Pb mixed PSCs showed efficiencies of 16.44% and 15.44%, respectively. In addition, the flexible Sn–Pb mixed PSCs demonstrated excellent bending durability, which retained over 80% of the original efficiency after 5000 bending cycles at a radius of 5 mm.

DMSO‐Free Solvent Strategy for Stable and Efficient Methylammonium‐Free Sn–Pb Alloyed Perovskite Solar Cells

AbstractHarmful Sn(IV) vacancies and uncontrolled fast crystallization commonly occur in tin–lead alloyed perovskite films. The typical dimethyl sulfoxide (DMSO) processing solvent is suggested to be the primary source of problems. Here, a DMSO‐free solvent strategy is demonstrated to obtain high‐performance Cs0.25FA0.75Pb0.5Sn0.5I3 solar cells. A rational solvent selection process via Hansen solubility parameters and Gutmann's donor number shows that N,N′‐dimethylpropyleneurea (DMPU) has a strong coordinate ability to form complete complexation with organic (formamidinium iodide) and inorganic (CsI, PbI2, and SnI2) components. This treatment suppresses the iodoplumbate (PbIn2‐n) or iodostannate (SnIn2‐n) preformed in precursor solution, thereby promoting pure intermediate complexes and retarding crystallization, realizing enlarged grain size, and improved film crystallinity. Additionally, it is demonstrated that DMPU‐based solvent system can further inhibit the oxidation of Sn(II) and reduced Sn(IV) content by nearly 75% due to its superior thermal and chemical stability. This DMSO‐free strategy generates a record efficiency of 22.41%, with a Voc of 0.88 V and a FF of 82.72% for the MA‐free Sn–Pb alloyed device. The unencapsulated devices display much‐improved humidity stability at 30 ± 5% relative humidity in air for 240 h, impressive thermal stability at 85 °C for 500 h, and promote continuous operation stability at maximum power point for 150 h.

Synthesis of Isostructural Intermetallic Sn-Pb-Bi-Pt Platform Materials for Catalytic Investigations.

The isostructural region (Sn,Pb,Bi)Pt has been established over a wide range of the quasi-ternary section of the quaternary phase diagram. A synthesis protocol was developed, and single-phase compounds were thoroughly characterized, revealing linear relationships between the volume of the unit cell and the substitution degree for the NiAs type of crystal structure. Together with the already established (Pb,Bi)Pt series, the isostructural cut at 50 atom % Pt forms an ideal platform to independently investigate the influence of electronic and structural properties for physical and chemical applications, such as electrocatalysis. The three binary endmembers SnPt, PbPt, and BiPt are active materials in a variety of electrocatalytic oxidation and reduction reactions such as methanol oxidation and oxygen reduction, respectively. By gradual substitution, a fully independent tuning of interatomic distances and electronic densities can be achieved without altering the crystal structure. This unique adaptability is gated behind the requirement of extended homogeneity ranges of at least quaternary intermetallic compounds. Here, we present this new platform for systematic investigations in (electro) catalysis.

Highly efficient and stable near-infrared photodetectors enabled from passivated tin–lead hybrid perovskites

Tin–lead perovskite-based photodetectors have a wide light-absorption wavelength range, which spans 1000 nm. However, the preparation of the mixed tin–lead perovskite films faces two great obstacles, namely easy oxidation of Sn2+ to Sn4+ and fast crystallization from tin–lead perovskite precursor solutions, thus further resulting in poor morphology and high density of defects in tin–lead perovskite films. In this study, we demonstrated a high-performance of near-infrared photodetectors prepared from a stable low-bandgap (MAPbI3)0.5(FASnI3)0.5 film modified with 2-fluorophenethylammonium iodide (2-F-PEAI). The addition engineering can efficiently improve the crystallization of (MAPbI3)0.5(FASnI3)0.5 films through the coordination binding between Pb2+ and N atom in 2-F-PEAI, and resulting in a uniform and dense (MAPbI3)0.5(FASnI3)0.5 film. Moreover, 2-F-PEAI suppressed Sn2+ oxidation and effectively passivated defects in the (MAPbI3)0.5(FASnI3)0.5 film, thereby significantly reducing the dark current in the PDs. Consequently, the near-infrared photodetectors showed a high responsivity with a specific detectivity of over 1012 Jones at 800 to near-1000 nm. Additionally, the stability of PDs incorporated with 2-F-PEAI has been significantly improved under air conditions, and the device with the 2-F-PEAI ratio of 400:1 retained 80% of its initial efficiency after 450 h storage in air without encapsulation. Finally, 5 × 5 cm2 photodetector arrays were fabricated to demonstrate the potential utility of the Sn–Pb perovskite photodetector in optical imaging and optoelectronic applications.

Preparation of Ti3SiC2–Sn(Pb) Cermet by SHS of Ti3SiC2 Porous Skeleton with Subsequent Spontaneous Infiltration with Sn–Pb Melt

Preparation of Ti3SiC2–Sn(Pb) Cermet by SHS of Ti3SiC2 Porous Skeleton with Subsequent Spontaneous Infiltration with Sn–Pb Melt

Bidirectional Anions Gathering Strategy Afford Efficient Mixed PbSn Perovskite Solar Cells.

Mixed lead-tin (PbSn) perovskite solar cells (PSCs) possess low toxicity and adjustable bandgap for both single-junction and all-perovskite tandem solar cells. However, the performance of mixed PbSn PSCs still lags behind the theoretical efficiency. The uncontrollable crystallization and the resulting structural defect are important reasons. Here, the bidirectional anions gathering strategy (BAG) is reported by using Methylammonium acetate (MAAc) and Methylammonium thiocyanate (MASCN) as perovskite bulk additives, which Ac- escapes from the perovskite film top surface while SCN- gathers at the perovskite film bottom in the crystallization process. After the optoelectronic techniques, the bidirectional anions movement caused by the top-down gradient crystallization is demonstrated. The layer-by-layer crystallization can collect anions in the next layer and gather at the broader, enabling a controllable crystallization process, thus getting a high-quality perovskite film with better phase crystallinity and lower defect concentration. As a result, PSCs treated by the BAG strategy exhibit outstanding photovoltaic and electroluminescent performance with a champion efficiency of 22.14%. Additionally, it demonstrates excellent long-term stability, which retains ≈92.8% of its initial efficiency after 4000 h aging test in the N2 glove box.

Analysis of Lead Smelting Technology in the Early Bronze Age Based on Smelting Slag from the Central Plains of China

To explore the source of Pb in Bronze Age artefacts from the Central Plains (Zhongyuan) in China, we investigated non-ferrous minerals from the Qingyuan archaeological site in Yuanqu County near the Zhongtiao Mountains. Fragments of smelting slag from the Erlitou cultural layer were collected. The smelting slag was investigated by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and lead isotope analysis. The SEM and EDS results confirmed that the slag contained Pb, Pb–As, and Cu–Pb–Sn inclusions and non-metal impurities such as low-Zn spinels. The XRD results signified that the bulk of the slag comprised Fe–Mn–Si phases. The chemical state of Pb was mainly Pb–O with some metallic Pb, as identified by XPS. The theoretical melting point was calculated using FactSage7.1 based on the composition and phase characterisation. The calculated temperature was 1100–1200 °C, which agreed well with the actual melting point of 1114–1354 °C. The slag composition and inclusion phases indicated that Pb–Zn–O ores with Mn and As were added during reduction smelting in Qingyuan. The raw materials of smelting included crude Pb with minor amounts of Cu, As, and Sn. Lead isotope analysis revealed that the lead materials produced in Qingyuan were likely transferred to Yanshi City in the Shang Dynasty. The findings of this study provide significant clues for exploring lead mineral production in the Central Plains during the Early Bronze Age.

Multifunctional Regulation of Highly Orientated Tin–Lead Alloyed Perovskite Solar Cells

Tin–lead (Sn–Pb) alloyed perovskites are promising candidates for next-generation photovoltaics due to their appropriate bandgaps for multijunction tandem solar cells, which can potentially overcome the Shockley-Queisser limit. However, their power conversion efficiency (PCE) and stability are still impeded by the poor absorber quality and defects caused by the oxidation of Sn2+. Here, we introduced trimethylsulfoxonium iodide (TMSI) as an additive along with SnF2 to fabricate Sn–Pb perovskite films with enlarged grains and improved film quality. TMSI restrained the oxidation of Sn2+ through molecular interactions, reducing the formation of detrimental Sn vacancies. As a result, a highly oriented Sn–Pb alloyed perovskite with a lower defect density was obtained, along with suppressed ion migration. The TMSI-treated Sn–Pb-based devices exhibited a champion PCE of 22.6% and outstanding stability, retaining 83% of their original efficiency after 6000 h of storage under a N2 atmosphere and maintaining 88% of their initial value after 1200 h of continuous one-sun illumination.

Surface Sn(IV) Hydrolysis Improves Inorganic Sn–Pb Perovskite Solar Cells

Cesium tin–lead (Sn–Pb) perovskites are exceptional for their combined capabilities in unlocking ideal bandgaps for solar cells and mitigating the stability issue faced by their hybrid organic–inorganic counterparts. But the development of high-performance solar cells using these materials is retarded by their inherent high density of detrimental Sn(IV) defects. Herein, we demonstrate a sequential surface treatment method, which entails a Sn(II) halide treatment to displace the buried Sn(IV) ions underneath the film surface, followed by a H2O treatment to hydrolyze the displaced Sn(IV) ions. The surface treatment induces chemical and microstructural reconstructions that significantly improve the optoelectronic properties and stability of perovskites. As a result, a power conversion efficiency of 16.79% and a T90 stability of 958 h are achieved, topping all previously reported performance parameters for inorganic Sn–Pb PSCs. This achievement further shortens the performance gap between all-inorganic and hybrid organic–inorganic Sn–Pb PSCs with sub-1.4 eV bandgaps.

Doping Strategies for Promising Organic-Inorganic Halide Perovskites.

Organic-inorganic halide perovskites (OIHPs) obtained tremendous attention due to their low cost and excellent properties. However, the stability and toxicity of Pb-based OIHPs (POIHPs), as well as the weakness of efficiency and stability in Sn-based OIHPs (SOIHPs), are still serious issues for commercial application. Notably, composition engineering is an effective and direct strategy for improving these issues along with the control and modification of properties. Recently, the doping strategies for POIHPs and SOIHPs are booming. Based on the relationship between properties and composition, the doping strategies for POIHPs and SOIHPs, aiming to provide a comprehensive review and guidance for the research are systematically summarized. Moreover, the doping strategies for Pb-Sn mixed OIHPs are also discussed. Finally, a brief perspective and conclusion toward future possible doping schemes and properties designment of POIHPs and SOIHPs are offered.