Carbon-based perovskite solar cells (C-PSCs) have attracted extensive attention due to their excellent environmental stability and low cost. 2D perovskite passivation has been widely employed as an effective strategy to enhance device stability in C-PSCs. However, this strategy often fails to simultaneously enhance efficiency and stability, owing to the random crystallization and disordered distribution of the 2D perovskite phase. Herein, phenethylammonium iodide and aluminum oxide (Al2O3) are employed to regulate the growth of 2D perovskites, forming an ordered interpenetrating alumina-2D perovskite structure. This unique architecture not only suppresses surface defects in the perovskite but also establishes an energy-level gradient, thereby improving energy-level alignment and facilitating interfacial charge extraction. Consequently, the hole transport layer-free C-PSCs fabricated under ambient air conditions achieved a power conversion efficiency of 18.1% and a T80 stability of 2500 h, demonstrating the effectiveness of the Al2O3-2D perovskite structure in enabling highly efficient and stable C-PSCs.

The degradation of perovskite solar cells (PSCs) under ultraviolet (UV) irradiation involves complex multiphysics interactions, yet the dynamic evolution of ion migration and defect generation at the interfaces remains elusive. This work employs embedded dual fiber Bragg grating sensors to monitor the operando evolution of interfacial tension within the perovskite active layer during UV exposure. Through control of the energy and intensity of UV light, a relationship was established between the evolution of interfacial stress in the perovskite and the decline in device power conversion efficiency (PCE), a degradation attributed to methylammonium cation escape. The stress evolution proceeds in two distinct stages: an initial phase of rapid stress accumulation, followed by a period of relaxation and stabilization. Dark recovery techniques show that efficiency loss is reversible during the initial stage but becomes irreversible in the succeeding phase. A critical PCE threshold was identified at the intersection of the stress evolution and PCE decay curves, serving as the primary diagnostic indicator for the device recovery window. Strategic intervention at this reversible phase increases the recoverable window by 140%, demonstrating the effectiveness of stress-guided recovery techniques for improving PSCs stability. Consequently, real-time stress monitoring enables a predictive failure framework that lays the groundwork for improving the long-term reliability of perovskite photovoltaics via mechanism-based maintenance protocols.

This study demonstrated that the optimized AlTiFeCrMoSi0.2 high-entropy alloy (HEA) coating can significantly improve the corrosion resistance of the T91 steel in high-temperature liquid lead-bismuth eutectic (LBE) environment. Compared with the commercial T91 steel, the thickness of oxide scale on the HEA-coated steel after 1000 h of corrosion in oxygen-saturated and low-oxygen LBE environment was reduced by factors of 5.7 and 13.11, respectively. Under saturated oxygen conditions, the oxide scale on T91 steel was dominated by Fe3O4 and FeCr2O4 spinel phases. In contrast, the coating system developed additional protective layers of TiO2 and continuous Al2O3.Under low oxygen environments, the oxide structure on T91 steel transitioned to a mixture of Cr2O3 and FeCr2O4, while the coating consistently formed TiO2 and continuous Al2O3 layers. The oxide layer of the coating effectively prevented the penetration of lead and bismuth, thereby suppressing the occurrence of localized dissolution corrosion. Theoretical calculations confirmed the critical roles of TiO2 and Al2O3 in enhancing the coating's resistance to liquid LBE corrosion. This study provides new insights into the development of LBE-corrosion-resistant approaches.

This study fabricated silicon (Si)-doped AlTiFeCrMoSix (x = 0, 0.2, 0.4, 0.6) high-entropy alloy (HEA) coatings on T91 steel using ultra-high-speed laser cladding (UHSLC). Microstructural analysis revealed a distinct three-zone grain structure, transitioning from columnar grains at the substrate interface to cellular grains in the mid-region and equiaxed grains at the surface. The addition of Si significantly influenced grain boundary characteristics, texture intensity, and grain size distribution. At Si0.2, the coating exhibited optimal elemental homogeneity and a peak surface hardness of 589.17 HV, while interfacial residual stress was reduced to 215 MPa owing to grain refinement and solid solution strengthening. In contrast, higher Si levels (0.4 and 0.6) promoted precipitate coarsening, grain boundary segregation, and elevated residual stress concentrations exceeding 270 MPa, resulting in compromised microstructural uniformity. High-temperature tensile tests at 550 degrees C further demonstrated that the Si0.2 composition enhanced ultimate tensile strength by 13.38% and yield strength by 6.72%, with a limited plasticity reduction of 6.76% elongation loss. Conversely, coatings with Si0.4 and Si0.6 displayed pronounced embrittlement, with elongation reductions of at least 22.17%. These findings establish x = 0.2 as the optimal Si concentration for achieving balanced strength-plasticity synergy in high-temperature corrosion-resistant coatings.

Nickel oxide (NiOx) serves as a promising inorganic hole transport layer (HTL) for efficient and stable Sn-Pb mixed perovskite solar cells (PSCs). However, intrinsic drawbacks of NiOx limit the efficiency of PSCs. In this study, we introduce 2D Ti3C2Tx MXenes, known for their high mobility and diverse functional groups, into NiOx HTLs to address these limitations. The addition of MXenes significantly enhances the conductivity of the NiOx layer without increasing the concentration of Ni3+. The abundant & horbar;OH and & horbar;O functional groups on MXenes form strong coordination bonds with Ni3(+) defects, effectively mitigating adverse reactions with organic cations and preventing oxidation of Sn2+ at the buried perovskite interfaces. Furthermore, these functional groups create additional nucleation sites that modulate perovskite crystallization kinetics, resulting in larger grain sizes and more compact buried interfaces. The dipoles formed by the MXenes improve energy level alignment at the NiOx/perovskite interfaces, enhancing hole extraction efficiency. Consequently, FASn0.5Pb0.5I3 PSCs utilizing MXene-NiOx HTLs achieved a remarkable power conversion efficiency (PCE) of 22.50% (20.04% certified), among the highest efficiencies reported for FA-based Sn-Pb PSCs with NiOx HTLs. Additionally, unencapsulated devices show improved stability, retaining approximately 80% of their initial PCE after 600 h of continuous operation at maximum power point.

The performance of air-processed perovskite solar cells (PSCs) is often compromised by the vulnerable perovskite/charge transport layer interface arising from exposure to ambient moisture during fabrication, which promotes nonradiative recombination, ion migration, and poor tolerance to reverse-bias stress. Conventional passivation strategies primarily focus on defect-density reduction and fail to address these issues simultaneously. Here, we report a dielectric-chemical interfacial engineering based on solution-processed metal oxide nanoparticles deposited at the perovskite/hole transport layer (HTL) interface. On one hand, the Pb-O coordination between the metal oxide and the perovskite surface chemically passivates Pb-related defects. On the other hand, the resulting high-κ dielectric environment screens residual charged defects and increases interfacial capacitance, thereby suppressing recombination, mitigating electric-field localization under reverse bias, and restraining ion migration. Among the investigated metal oxides, ZrO2 provides the most effective interfacial passivation and dielectric screening, leading to notable efficiencies of 25.60% and 22.85% for the PSCs and perovskite solar modules (PSMs), respectively. Moreover, the resulting devices exhibit excellent operational robustness, as evidenced by the increased reverse breakdown voltage from -1.8 V to -4.0 V and the retention of 96.8% of the initial efficiency after 1470 h of maximum power point tracking (MPPT) with encapsulation.

Organic-inorganic halide perovskites have recently emerged as a class of materials with great potential in various sensing applications. However, most research has focused on their use in electrochemical sensors, where humidity and temperature typically produce similar response patterns. In this work, we report an optical fiber sensor based on organic-inorganic halide perovskite that exhibits opposite wavelength shift directions in response to humidity and temperature, with blue-shift occurring under humidity and red-shift under temperature. The sensor is fabricated by a tapered seven-core fiber (SCF) surface-functionalized with a CH3NH3PbI3 (MAPbI3) thin film that acts as a highly responsive sensing layer. It undergoes rapid and pronounced refractive index changes upon exposure to humidity or temperature due to the formation of distinct degradation products, which in turn modulate cladding mode interference in the tapered fiber structure. The resulting sensor exhibits excellent linearity and fast initial response, delivering peak sensitivities of 19.88 pm/%RH (33-93% RH) and 16.52 pm/degrees C (40-150 degrees C) obtained from linear fitting within the first 5 min of exposure. This approach offers a cost-effective method for monitoring environmental integrity in sealed systems. The compact and flexible optical fiber allows easy co-encapsulation with the target device for internal monitoring, and the intrusion levels of humidity and temperature within the device can be evaluated via the degradation degree of the MAPbI3 film.

This study investigates the hydrogen embrittlement susceptibility of laser melting deposition (LMD)-produced Ti-6Al-4V alloy with different build orientations (0°, 45°, 90°) through electrochemical hydrogen charging, slow strain rate testing, and microstructural characterization. Ti-6Al-4V alloys are widely used in marine and offshore engineering, where cathodic protection and corrosion reactions can generate hydrogen, leading to hydrogen ingress and potential embrittlement. Results show that prolonged hydrogen charging induces hydride formation, α-phase fragmentation, and β-phase dissolution, significantly degrading corrosion resistance and mechanical properties. Hydrogen embrittlement susceptibility exhibits notable anisotropy: elongation reductions for 0°, 45°, and 90° specimens are 40.1%, 40.8%, and 29.4%, respectively. The relatively superior resistance observed in the 90° orientation may be associated with its single-layer structure and more uniform dimple distribution. In contrast, the multilayer interfaces in other orientations are likely to serve as preferential sites for hydrogen accumulation, which may contribute to the increased embrittlement susceptibility. This research reveals the failure mechanism of LMD Ti-6Al-4V in hydrogen environments and supports its application in marine engineering.

This study investigates laser-cladded high entropy alloy (HEA) coatings on high-speed train axles to enhance wear resistance under specific fretting conditions. Axles in humid and acidic environments absorb hydrogen, leading to accumulation in grain boundaries, which weakens their structure and causes damage under alternating stress. Despite this, the impact of hydrogen damage on the fretting wear behavior of HEA coatings has not been explored. To address this, we performed fretting wear tests on a laser-cladded FeCoCrNiMo0.2 coating and a GCr15 steel ball friction system, evaluating their performance before and after hydrogen exposure. The results of the study indicate that under a constant load of Fn = 10N and a displacement amplitude of D = 50 mu m, the friction coefficient, maximum wear depth, wear volume, and wear rate increased when the system was in the hydrogen charging state compared to the non-hydrogen charging state. Specifically, the friction coefficient increased from 0.60 to 0.93, the maximum wear depth increased from 2.82 mu m to 3.63 mu m, the wear volume increased from 14.106 x 104 mu m3 to 22.098 x 104 mu m3, and the wear rate increased from 28.213 x 10-6 mm/Nm to 36.600 x 10-6 mm/Nm. Under the hydrogen charging state, the friction coefficient, maximum wear depth, wear volume, and wear rate all increased. This is due to hydrogen damage, including the formation of pitting pits and cracks on the surface of the coating, stress concentration, and brittle failure caused by hydrogen infiltration into the material. The presence of hydrogen makes the surface of the coating more prone to detachment, resulting in finer wear debris, deeper grooves, and increased oxidation. These factors accelerate the wear of the coating. This finding will contribute to the development and improvement of advanced surface modification techniques for materials in the hydrogen environment.

Flexible perovskite solar cells (F-PSCs) are appealing for their flexibility and high power-to-weight ratios. However, the fragile grain boundaries (GBs) in perovskite films can lead to stress and strain cracks under bending conditions, limiting the performance and stability of F-PSCs. Herein, we show that the perovskite film can facilely achieve in situ bifacial capping via introducing 4-(methoxy)benzylamine hydrobromide (MeOBABr) as the precursor additive. The spontaneously formed MeOBABr capping layers flatten the grain boundary grooves (GBGs), enable the release of the mechanical stress at the GBs during bending, rendering enhanced film robustness. They also contribute to the reduction of the residual strain and the passivation of the surface defects of the perovskite film. Besides, the molecular polarity of MeOBABr can result in surface band bending of the perovskite that favors the interfacial charge extraction. The corresponding inverted F-PSCs based on nickel oxide (NiOx)/poly(triaryl amine) (PTAA) hole transport bilayer reach a 23.7% power conversion efficiency (PCE) (22.9% certified) under AM 1.5 G illumination and a 42.46% PCE under 1000 lux indoor light illumination. Meanwhile, a robust bending durability of the device is also achieved. The performance and stability of flexible perovskite solar cells are limited by the fragile grain boundaries in perovskite films. Here, authors achieve in-situ bifacial capping to flatten the grain boundary grooves and demonstrate stable flexible inverted devices with maximum efficiency of 23.7%.

Fluorescent material was introduced at the hole-selective contact to simultaneously enhance the light-harvesting efficiency and photo-stability of inverted perovskite solar cells. The device achieved improved PCE via a 4.4% increase in photocurrent, while it retained ∼80% of the initial efficiency after 1000 hours of UV illumination.

Ambient-air fabrication of perovskite solar cells (PSCs) offers substantial advantages for scalable commercialization. However, ambient moisture promotes the formation of undesirable DMSO-based adducts that deteriorate perovskite (PVK) film crystallinity and lead to poor interfacial contact, particularly at the buried interface with the metal oxide (MO) charge transport layer, thereby compromising the device efficiency and stability. Here, we report a universal strategy employing hydrazide additives to effectively suppress DMSO-based adducts by competitively coordinating with perovskite precursors, while simultaneously binding strongly with both the MO and PVK through Lewis acid-base interactions and hydrogen bonding. These interactions promote the removal of residual DMSO at the MO/PVK interface, leading to high-quality perovskite films with homogenized MO/PVK contact across a wide humidity range in ambient air and dual-side passivation that effectively suppresses interfacial recombination losses. As a result, the best-performing PSCs deliver power conversion efficiencies (PCEs) of 25.07% and 24.75% for the SnO2-based regular and NiOx-based inverted architectures, respectively, representing >15% improvement over the reference devices. Notably, this homogenized MO/PVK contact is achieved without additional interfacial treatment, making it ideally suited for scalable device fabrication, as demonstrated by the mini perovskite solar modules (PSMs, 4.6 cm x 4.6 cm) attaining PCEs of 22.65% (regular) and 21.73% (inverted). The devices also show excellent operational stability under maximum power point tracking (MPPT) and enhanced resistance to light, thermal, and humidity stress according to ISOS protocols. Additionally, this strategy shows excellent compatibility with the blade-coating technique, highlighting its strong potential for large-area PSM production.

The Ti-6Al-4 V alloy produced by laser powder bed fusion (LPBF) is one of the most typical titanium (Ti) alloys, combining the characteristics of alpha-Ti and beta-Ti. Due to its low density, high strength, good toughness, and biocompatibility, it is widely used in fields such as aerospace, high-speed trains, and medical implants. However, its specific microstructure is sensitive to hydrogen absorption and embrittlement, which limits its broader application. This paper investigates the effects of doped graphene nanoflakes (GNFs) on the microstructure and hydrogen embrittlement (HE) resistance of LPBF-formed titanium matrix composites (TMCs) through microscopic characterization and slow strain rate tensile testing with electrochemical hydrogen pre-charging. The results indicate that the presence of hydrogen atoms adversely affects both the strength and plasticity of the composites with varying graphene content, with increased sensitivity to HE as the graphene content rises. The strength loss rates for composites with 0 wt%, 0.1 wt%, and 0.2 wt% GNFs are 7.29 %, 4.84 %, and 19.23 %, respectively, while the plasticity loss rates are 51.70 %, 59.91 %, and 60.57 %. The fracture mode is primarily a mixed ductile-brittle fracture, with the crack initiation and propagation mechanisms transitioning from trans- granular fracture to intergranular fracture. These findings provide a theoretical basis and technical support for the engineering application of LPBF-formed TMCs in hydrogen-rich service environments.

Pre-corrosion fatigue is a critical factor affecting the safe operation of aircraft. In this study, the corrosion behavior of the aircraft structural material 2195 Al-Cu-Li alloy and the effect of precorrosion on fatigue performance were investigated. In addition, the fatigue life prediction model for the pre-corroded 2195 Al-Cu-Li alloy was developed on the basis of damage mechanics. Results indicated that pre-corrosion induces pits and hydrogen embrittlement damages on the surface of the sample, resulting in the degradation of tensile fracture strain and fatigue performance. The T1 phase induces pit initiation in the alpha-Al matrix by galvanic corrosion. The fatigue cracks prefer to initiate from the corrosion pits. A fatigue life prediction model based on damage mechanics is developed, and the predicted results are consistent with the fifth-errorfactor band. The findings of this study will provide a comprehensive understanding of the fatigue behavior of 2195 Al-Cu-Li alloy.

X80 pipeline steel is a key material in the field of oil and gas transportation. Its damage behavior in a hydrogen-filled environment directly affects pipeline safety. In this study, through hydrogen permeation experiments and slow strain rate tensile tests, the electrochemical responses and hydrogen-induced cracking behaviors of X80 base metal and welded joints under hydrogen filling conditions in both AC and DC were systematically compared. The results show that when the base material is filled with hydrogen at 20 mA/cm2 AC, the hydrogen permeation flux is the largest, and the overall hydrogen permeation parameter of the welded joint is lower than that of the base material. High-frequency polarization promotes hydrogen permeation, but anodic corrosion products at high current densities can impede hydrogen entry. The slow strain rate tensile test further confirmed that the mechanical properties of the material declined more significantly under direct current hydrogen charging, and the sensitivity to stress corrosion cracking was higher. Under alternating hydrogen charging conditions, due to the alternating effects of hydrogen charging at the cathode and corrosion at the anode, a relatively low hydrogen embrittlement sensitivity is exhibited.

High-entropy alloys (HEAs) have garnered significant global interest due to their outstanding properties. This study investigates the structural stability and mechanical properties of FeCoCrNiMox (x = 0, 0.4, 0.5, 0.8, 1.3) HEAs using a first-principles approach coupled with the special quasi-random structure (SQS) method. Of the alloys examined, all except FeCoCrNiMo1.3 were found to be thermodynamically and dynamically stable. Elasticity calculations revealed that molybdenum improves the ductility and anisotropy of the alloys, though with a slight decrease in strength and stiffness, as confirmed by electronic structure analysis. Defect-free FeCoCrNiMo0.5 HEAs coatings were then prepared using laser cladding and characterized for their microstructure and hardness. The coating exhibited a transition from columnar crystals at the bottom to equiaxed crystals at the surface, forming a honeycomb-like structure. Inside the crystal cells, high-density dislocations and σ-phase were observed. Elasticity calculations of the σ-phase confirmed its high hardness, low ductility, and classification as a brittle, hard phase.

The inverted perovskite solar cells (PSCs) based on inorganic metal oxide hole transport layers (HTLs) bear the merits of high device stability and low material cost. However, the existence of metal-vacancy defects on the surface of the metal oxide layer is a key constraint on achieving high efficiency and stability, like the case of the well-known nickel oxide (NiOx) HTL. Here, a cobalt oxide (CoOx) HTL with the defect-less surface is prepared by a solution process using Co(OH)(2) as the cobalt source and water as an eco-friendly solvent for the first time. The PSCs based on CoOx HTL show superior thermal and ultraviolet stability over the conventional NiOx counterparts. Theoretical calculations reveal that CoOx has higher formation energy of metal-vacancy defect as well as higher interfacial adhesion energy than NiOx, resulting in a chemically stable HTL/perovskite interface. After further manipulating the microstructure and the electronic properties of the CoOx HTL via magnesium acetate doping, a 22.35% efficiency is achieved with an ambient-processed FA(0.4)MA(0.6)I(3) light-absorbing layer. Such an efficiency exceeds all of the existing results reported for CoOx-based PSCs and a higher value of >24% is attainable via facile interface modification. The according device also demonstrates robust operational stability in the air without encapsulation.

We present a facile strategy to improve the conductivity and homogeneousness of nickel oxide nanoparticles (NiOx NPs). The inverted flexible perovskite solar cells (F-PSCs) prepared with NiOx achieved impressive efficiencies of 22.68% under AM 1.5G and 35.59% under 1000 lux, respectively.

This study investigated the effect of pre-deformation on the corrosion fatigue crack propagation (CFCG) of Al-Mg-Zn alloy in a corrosive environment. Tensile tests at different pre-deformation levels and molecular dynamics simulations analyzed changes in dislocation density. Corrosion fatigue experiments were conducted in a 3.5% NaCl solution at room temperature, and crack propagation morphology was characterized using electron backscatter diffraction (EBSD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The results showed that tensile strength increased by 2.63% and 10.00% for 5% and 10% pre-deformation, respectively. The crack propagation threshold values were L2 (6.36 MPa·m1/2) > L0 (6.05 MPa·m1/2) > L1 (5.13 MPa·m1/2), attributed to increased dislocation density and material strength. At 5% pre-deformation, dislocation pile-ups created stress concentrations that facilitated crack propagation. In contrast, the non-uniform dislocation distribution at 10% pre-deformation enhanced both material strength and resistance to crack growth.