Future Materials Research Articles

Preparation of amorphous silicon-doped Y2O3 aerogel enabling nonlinear optical features for ultrafast photonics

Abstract Amorphous aerogels with the microscopic nanoscale three-dimensional meshes provide superb platforms for investigating unique physicochemical properties. In order to enhance the physical, thermal and mechanical performances, one efficient and common approach is integrating diverse functional materials. Herein, we report a simple strategy to fabricate the amorphous silicon doped Y2O3 aerogels with the post-gelation method under the N2/EtOH supercritical atmosphere. The impact of Si concentration on the nonlinear optical properties is investigated for the first time. The maximum modulation depth is 1.65 % with a saturation intensity of 0.78 MW cm−2 with the 1-ps laser excitation at 1590 nm. Finally, we incorporated the silicon-doped Y2O3 aerogel based saturable absorber (SA) into an erbium-doped fiber laser (EDFL) and achieved various mode-locking operations at different wavelengths in the super C band, in terms of the conventional soliton, harmonic soliton molecules pulses, and dual-wavelength soliton mode-locking. Overall, this work confirms that amorphous silicon-doped Y2O3 aerogels are good nonlinear optical materials and pave a way for the ultrafast photonic and nonlinear optical applications with amorphous materials in near future.

Using Corpus Linguistics in Materials Development and Teacher Education

In published ELT materials, norms relating to written language often dominate, at the expense of spoken language. This dominance of writing typically arises as the features characteristic of everyday spoken language do not reflect the rather neat syllabi expected by teachers and students, globally. Furthermore, there are deeply held opinions relating to the usage and acceptability of features of spoken language. As a result, features of spoken language are often not represented in mainstream materials, despite a perennial request from learners for more ‘conversation’. One potential means to meet such a request is by employing corpus linguistics and spoken language research to inform ELT materials development and teacher education. Responding to this issue, this paper draws on findings from a corpus-based conversation analysis of spontaneous spoken British English to conduct workshops on materials development. The goal of these workshops is to gain a comprehensive perspective on the affordances of corpus linguistics for ELT materials development from core stakeholders: teachers. Through a grounded theory-based thematic analysis of lesson plans, recorded discussions, and survey responses, the findings of this study demonstrate that teachers find value in corpus linguistics research. Specifically, the teachers’ insights offer recourse for developing strategies for exploiting corpora better in future ELT materials development. Moreover, teachers signalled effective means through which corpus linguistics can be embedded in future teacher education.

Potential plasma facing materials: A case study on CeB6 particulate reinforced W–1Ni matrix composites produced via different sintering techniques

Tungsten (W) is the most promising material for future plasma-facing materials. Its alloys or composites reinforced with various compounds have been studied to improve the irradiation resistance of W. This study aimed to investigate the effect of boron-containing reinforcement in the W matrix against He+ ion irradiation. Cerium hexaboride (CeB6) particulates, which have high neutron shielding properties, were incorporated into the W matrix pre-alloyed by 1 wt% Ni (W1Ni). CeB6 powders were home-made and prepared from CeO2/Mg/B2O3 powder blends via mechanochemical synthesis and purification steps. 1, 5, and 10 wt% CeB6 powders were added to pre-alloyed W1Ni by mechanical alloying, and then they were consolidated by using pressureless sintering (PS, 1400 °C, 1 h) and spark plasma sintering (SPS, 1410 °C, 1 min) techniques. CeB6 particle-reinforced W1Ni composites contained different amounts of reinforcements were prepared by two different sintering methods and were compared with respect to their compositional, microstructural, and microhardness properties and wear and irradiation behaviors. Based on the results, increasing the CeB6 reinforcement amount in the composite triggered the formation of the W2B phase, especially in the W1Ni–10CeB6 composite after both sintering methods. The mechanical and irradiation properties were enhanced more by increasing the CeB6 amount in the case of using the SPS method. When compared to other sintered samples, the SPS'ed W1Ni–10CeB6 composite has the lowest specific wear rate of ∼4 × 10−7 mm3/Nm and the maximum hardness value of ∼21 GPa. According to surface deformation, the W1Ni–5CeB6 composite exhibited comparatively higher resistance to He+ ion irradiation.

Improved thermal properties and CMAS corrosion resistance of high-entropy RE zirconates by tuning fluorite-pyrochlore structure

The order-disorder transition (ODT) of RE zirconate (RE2Zr2O7) has received much attention due to its potential applications in the design of thermal barrier coatings (TBCs). A series of high entropy RE zirconates (RE = La, Sm, Gd, Er and Lu) were designed and synthesized in order to regulate the fluorite-pyrochlore phases, and to investigate the effect of phase composition on the microstructures and performances. The results showed that the sintering temperature, as well as equivalent ion radius, played an important role in regulating the phase transformation of fluorite-pyrochlore. The coexistence of pyrochlore-fluorite phases not only can result in the decrease in grain size but also increased the lattice strain of each phase, thereby enhancing the phonon scattering and contributing to the reduction in the thermal conductivity. The CMAS corrosion resistance was mainly related to phase compositions, and the thicknesses of reaction layer decreased gradually with the increasing fluorite phase content. The results will provide theoretical guidance for the microstructural design of high entropy RE zirconates as next generation TBC materials in future.

Effects of beam scanning modes on ion-irradiated iron microstructure

Neutron induced damage in future nuclear materials can be studied using heavy ion beams only if the differences in the microstructure evolution are well understood. Large variations in the damage dose rate, caused by scanning of the ion beam, can alter the microstructure compared to steady-state irradiation. We study the effect of scanning on the microstructure by irradiating pure iron with a 10 MeV Fe ion beam to a dose of 0.2 dpa. The beam is scanned in one direction with frequencies of 200 Hz and 10 kHz. Different shapes of the beam are also used to study the effect of dose variation. All of the irradiations are conducted at room temperature using the DiFU chamber at RBI. TEM analysis shows differences between the narrow beam and defocused irradiation modes, including unusual void formation observed at 10 kHz. A wider beam reduces the effect of scanning speed and no voids are found in this scanning case.

Research progress and application of high efficiency organic solar cells based on benzodithiophene donor materials.

In recent decades, the demand for clean and renewable energy has grown increasingly urgent due to the irreversible alteration of the global climate change. As a result, organic solar cells (OSCs) have emerged as a promising alternative to address this issue. In this review, we summarize the recent progress in the molecular design strategies of benzodithiophene (BDT)-based polymer and small molecule donor materials since their birth, focusing on the development of main-chain engineering, side-chain engineering and other unique molecular design paths. Up to now, the state-of-the-art power conversion efficiency (PCE) of binary OSCs prepared by BDT-based donor materials has approached 20%. This work discusses the potential relationship between the molecular changes of donor materials and photoelectric performance in corresponding OSC devices in detail, thereby presenting a rational molecular design guidance for stable and efficient donor materials in future.

Impact detection method based on the ratio of mechanoluminescence intensity

This paper proposes an impact detection method based on the ratio of mechanoluminescence (ML) intensity, as an improvement over traditional methods that rely on absolute ML intensity. The study utilized two types of ML materials, ZnS:Cu2+ and ZnS:Mn2+, which were physically mixed and embedded them in polydimethylsiloxane (PDMS) to fabricate a flexible film sensor. A drop ball experimental setup was constructed, and the ML spectrum of the film sensor under the impact of a small ball was collected through a spectrometer. This established the relationship between impact velocity and the ratio of ML intensities. Experiments proved that the distance of spectral collection has a minimal effect on the measurement results of this method. Compared to traditional methods based on absolute ML intensity, this method has stronger resistance to environmental interference and better applicability. This new impact detection method based on the ratio of ML intensities has broad application prospects in future engineering applications, safety assessments, and material testing.

High-Throughput Screening of Sulfur Reduction Reaction Catalysts Utilizing Electronic Fingerprint Similarity.

The catalytic performance is determined by the electronic structure near the Fermi level. This study presents an effective and simple screening descriptor, i.e., the one-dimensional density of states (1D-DOS) fingerprint similarity, to identify potential catalysts for the sulfur reduction reaction (SRR) in lithium-sulfur batteries. The Δ1D-DOS in relation to the benchmark W2CS2 was calculated. This method effectively distinguishes and identifies 30 potential candidates for the SRR from 420 types of MXenes. Further analysis of the Gibbs free energy profiles reveals that MXene candidates exhibit promising thermodynamic properties for SRR, with the protocol achieving an accuracy rate exceeding 93%. Based on the crystal orbital Hamilton population (COHP) and differential charge analysis, it is confirmed that the Δ1D-DOS could effectively differentiate the interaction between MXenes and lithium polysulfide (LiPS) intermediates. This study underscores the importance of the electronic fingerprint in catalytic performance and thus may pave a new way for future high-throughput material screening for energy storage applications.

High-solution emission characters and health risks of volatile organic compounds for sprayers in automobile repair industries.

The increasing automobile repair industries (ARIs) with spray facilities have become an important volatile organic compound (VOC) pollution source in China. However, the VOC health risk assessment for long-term exposure in ARIs has not been well characterized. In this study, though sampled VOCs from 51 typical ARIs in Beijing, the relationship between emission patterns, average daily exposure concentrations (EC), and health risks was comprehensively analyzed with the health assessment method. Results showed that concentrations of 117 VOCs from the samples ranged from 68.53 to 19863.32 μg·m-3, while the ARI operator's daily VOC inhalation EC was 11.24-1460.70 μg·m-3. The organic VOC (OVOC) concentration accounted for 73.16 ~ 94.52% in the solvent-based paint workshops, while aromatics were the main VOC component in water-based paint spraying (WPS) workshops, accounting for 70.08%, respectively. And the method of inhalation exposure health risk assessment was firstly used to evaluate carcinogenicity and non-carcinogenicity risk for sprayers in ARIs. The cumulative lifetime carcinogenic risk (LCR) for 24 sampled VOCs were within acceptable ranges, while the mean hazard index (HI) for 1 year with 44 sampled VOCs was over 1. Among them, ethyl alcohol had a high carcinogenic risk in both mixed water-based paint (MP) and solvent-based paint workshops. The mean HI associated with aromatics were 2.88E - 3 and 4.30E - 3 for 1 h in MP and WPS workshops. O-ethyl toluene and acetone are VOC components that need to be paid attention to in future paint raw materials and spraying operations. Our study will provide the important references for the standard of VOC occupational exposure health limits in ARIs.

Modeling of compressive stress in AlSi10Mg alloys using feed-forward neural networks

This study addresses the challenge of modeling compressive stress in AlSi10Mg composites by introducing a method that employs feedforward artificial neural networks (ANNs) and their interpretability, which helps to simulate and analyze material behavior under various conditions. The main objective is to develop a predictive ANN model that can effectively simulate material responses under several factors, incorporating diverse testing parameters and material specifications related with its synthesis. An optimized ANN model, featuring eleven neurons in its hidden layer, was used and demonstrated high predictive accuracy, achieving R 2 values exceeding 0.94. Additionally, a SHAP interpretability analysis was conducted to assess the influence of key factors such as strain and material conditions on the stress response. The results highlight the significant role of material synthesis processes, compared to the strain rate, in the stress response. In conclusion, this method presents a comprehensive tool for studying complex stress behaviors in AlSi10Mg-based composites , offering insights that could guide future material development and research.

Multicolour room temperature phosphorescence of carbon nitride nanoparticles in sodium borohydride and borax matrix

Carbon nitride based materials find applications in photocatalysis, sensing, and bioimaging. The fluorescence properties of carbon nitride based nanomaterials is widely studied. However, its phosphorescence phenomenon is relatively less explored. Herein, we report a simple and economic one step thermal synthesis of highly fluorescent pure carbon nitride nanoparticles (CNNPs) from organic solvent formamide at 220 °C, just above its boiling point without any further passivation or purification.The fluorescent CNNPs is dispersed in sodium borohydride and borax which act as suitable host matrix resulting in activation of persistent room temperature phosphorescence of CNNPs with high phosphorescence lifetimes of 1.144 s and 0.737 s respectively. Moreover, the CNNPs-Sodium borohydride composite display tricolour, blue, green and yellow-orange phosphorescence under 254 nm, 365 nm and 400 nm light respectively while CNNPs-Borax composite show dual blue and green phosphorescence under 254 nm and 365 nm UV light respectively. Hence, these CNNPs-Composite may be used as multicolour anti-counterfeiting materials in future.

Recent Advancements in α‐Ga2O3Thin Film Growth for Power Semiconductor Devices via Mist CVD Method: A Comprehensive Review

AbstractThis review discusses the impact of alpha‐gallium oxide (α‐Ga2O3) on potential high‐power device applications. To date, there are high requirements for efficient high‐power delivery and low‐power loss device material in power industries. III‐VI oxide semiconductor family, α‐Ga2O3,is recognized as a promising, future power semiconductor material owing to its ultrawide bandgap of 5.3 eV, high breakdown field of 10 MV cm−1, and a large Baliga's figure of merit. A highly expected α‐Ga2O3power semiconductor electronic device (Schottky barrier diode and field effect transistor) can perform better than conventional semiconductor materials Si, SiC, and GaN. However, there is a lack of research into using mist CVD to cultivate high‐quality α‐Ga2O3for high‐power devices like FETs and SBDs. Currently, the mist CVD‐grown α‐Ga2O3thin film power device is still in its early stages, and one of the main reasons for this is defects of the thin film, which impede material electron mobility. The purpose of writing this article is to provide an overview of the development of α‐Ga2O3heteroepitaxial thin film by the mist CVD process for use in high‐power devices such as Schottky barrier diodes (SBD) and field effect transistors (MOSFET). 1. α‐Ga2O3α‐Ga2O3. Furthermore, multiple viewpoints highlight the challenges and future trends toward device performance sustainability in a scientific society.

Mechanism of hydrogen isotope exchange for tritium removal in plasma-facing materials: a multi-scale investigation

The safety of future fusion reactors is critically dependent on the tritium (T) retention in plasma-facing materials. Hydrogen isotope (HI) exchange offers a method to redistribute HIs within solid materials, presenting a feasible approach for removing T from bulk materials and trapped by strong trapping sites. Nonetheless, unraveling the intricate mechanism behind HI exchange remains an urgent yet formidable challenge. This study undertakes a comprehensive investigation into the mechanism of HI exchange in tungsten materials across multiple scales. First, we developed a multi-component hydrogen isotope transport and exchange model (HIDTX) based on classical rate theory. The model validation was further carried out, demonstrating good consistency with the well-controlled laboratory experiments. From the results of different comparative models in HIDTX, it is found that the reduction in deuterium retention due to HI exchange was primarily driven by three synergistic effects: competitive re-trapping, collision, and swapping effects. Through molecular dynamics (MD) and first-principles calculations, the microscopic mechanism of HI exchange was revealed to be that the presence of hydrogen atoms in the interstitial sites surrounding a vacancy in tungsten decreased the binding energy between the vacancy and hydrogen. Meanwhile, we discovered that the combination of thermal desorption and HI exchange can significantly lower the temperature required for the hydrogen removal and enhance the removal rate. Particularly, the hydrogen removal time can be shortened by approximately 95% with simultaneous HI exchange compared to that with only thermal desorption. This work provides a practical guideline for comprehending and subsequently designing for efficient T removal in future nuclear fusion materials.

Effects of scattering mechanisms on thermoelectric properties of bismuth

This discussion explores various facets of thermoelectric materials research, focusing on bismuth (Bi) and its semiconductor form (Bi'). It highlights Bi's semiconductor nature and the importance of Bi' in thermoelectric materials. The thermoelectric properties of Bi' are examined, emphasizing temperature-dependent superiority. Electronic lifetimes and thermoelectric properties, considering scattering mechanisms like acoustic and ionized impurity scattering, is discussed. Bi's thermoelectric properties are influenced by temperature and carrier concentration, showing potential superiority over traditional Bi, especially at room temperature. The results show that ZT reaches a maximum value of 0.59 at 300K. The intricate relationship between Bi' thermoelectric performance, temperature, and scattering mechanisms, particularly ionized impurity scattering, is elucidated. In addition, Bi' holds promise for superior thermoelectric performance, offering valuable insights for future material development.

Blue-Green Horizons: Redefining Alginate Bioplastics with Spirulina Dyes

AbstractThis study introduces a novel, eco-friendly approach for the extraction and application of Spirulina (Sp.) pigments in alginate bioplastics, representing a significant advancement over traditional dyeing methods. The research explores a zero waste model process in a Fab Lab setting, involving three stages, liquid dye preparation, fibre dyeing, and bioplastic dyeing, with a focus on utilizing all by-products sustainably. In the liquid dye preparation phase, vibrant blue-green pigments were successfully extracted from Spirulina powder. The colour depth depended on the Spirulina concentration and the precipitation method used, with pH playing a critical role in achieving a range of green–blue hues. The fibre dyeing phase tested Spirulina dyes on various natural fibres, examining the impact of alum mordant pre-treatment on colour absorption and stability. Optimal dyeing results were obtained with a 1:1 ratio of Spirulina-filtered powder suspension to alum acid precipitation solution at a pH of 4. The techniques optimized were then applied to alginate bioplastics, including bio-yarns and bio-films, yielding a wide spectrum from green to blue. Bio-yarns showed better colour retention compared to bio-films, possibly due to residual alum. However, challenges in long-term colour stability and structural integrity against environmental factors like oxidation and humidity were observed. The study contributes valuable insights into the application of natural dyes in bioplastics, particularly in achieving blue and green shades with a Spirulina zero waste model. This work is significant for future sustainable material science research and emphasizes the importance of balancing aesthetic, functional, and environmental factors in circular design. Graphical Abstract

Emerging Two-Dimensional Carbonaceous Materials for Electrocatalytic Energy Conversions: Rational Design of Active Structures through High-Temperature Chemistry.

Electrochemical energy conversion and storage technologies involving controlled catalysis provide a sustainable way to handle the intermittency of renewable energy sources, as well as to produce green chemicals/fuels in an ecofriendly manner. Core to such technology is the development of efficient electrocatalysts with high activity, selectivity, long-term stability, and low costs. Here, two-dimensional (2D) carbonaceous materials have emerged as promising contenders for advancing the chemistry in electrocatalysis. We review the emerging 2D carbonaceous materials for electrocatalysis, focusing primarily on the fine engineering of active structures through thermal condensation, where the design, fabrication, and mechanism investigations over different types of active moieties are summarized. Interestingly, all the recipes creating two-dimensionality on the carbon products also give specific electrocatalytic functionality, where the special mechanisms favoring 2D growth and their consequences on materials functionality are analyzed. Particularly, the structure-activity relationship between specific heteroatoms/defects and catalytic performance within 2D metal-free electrocatalysts is highlighted. Further, major challenges and opportunities for the practical implementation of 2D carbonaceous materials in electrocatalysis are summarized with the purpose to give future material design guidelines for attaining desirable catalytic structures.

Ni-based PCS-derived adsorbent with superior electromagnetic absorption capacity and reduced radar cross section

Low-cost and high-efficiency electromagnetic wave absorption materials had extremely broad application prospects in the realms of military and civilian domains. A series of Ni-based PCS-derived adsorbents made from precursor infiltration pyrolysis at different pyrolysis temperatures were investigated in this research. The results showed that after being pyrolyzed at 1200 °C, the Ni-based PCS-derived adsorbent possessed the lowest reflection loss value of −59.52 dB, while it reached a peak effective absorption bandwidth of 2.84 GHz with 1000 °C treatment, of which the calculated electromagnetic absorption efficiency was meanwhile the best. Besides, the simulation results showed that the adsorbent after being pyrolyzed at 1000 °C could minimize the radar cross section of the target, of which the strongest radar cross section reduction value was 21.34 dB·m2, significantly enhancing its stealth performance. Therefore, the Ni-based PCS-derived adsorbent possessed great electromagnetic wave absorption performances under conditions of high-temperature pyrolysis, which provided a reference for future electromagnetic wave absorption material design.

Optical Properties Prediction for Red and Near-Infrared Emitting Carbon Dots Using Machine Learning.

Functional nanostructures build up a basis for the future materials and devices, providing a wide variety of functionalities, a possibility of designing bio-compatible nanoprobes, etc. However, development of new nanostructured materials via trial-and-error approach is obviously limited by laborious efforts on their syntheses, and the cost of materials and manpower. This is one of the reasons for an increasing interest in design and development of novel materials with required properties assisted by machine learning approaches. Here, the dataset on synthetic parameters and optical properties of one important class of light-emitting nanomaterials - carbon dots are collected, processed, and analyzed with optical transitions in the red and near-infrared spectral ranges. A model for prediction of spectral characteristics of these carbon dots based on multiple linear regression is established and verified by comparison of the predicted and experimentally observed optical properties of carbon dots synthesized in three different laboratories. Based on the analysis, the open-source code is provided to be used by researchers for the prediction of optical properties of carbon dots and their synthetic procedures.

Mitigating Climate Change through Catalytic Conversions of CO2: A review

In the pursuit of a carbon-neutral economy, CO2 catalytic hydrogenation to methanol emerges as a pivotal technology for mitigating CO2 and addressing the manufacturing needs of future fuels, chemicals, and materials. The development of this technology not only offers solutions to environmental challenges, such as the greenhouse effect, but also facilitates the effective utilization of CO2 resources. The aims of this review is reveal intuitions into the structural and surface properties of heterogeneous catalysts, emphasizing the interface between metal and support. The exploration of these factors delves into their functions in reaction mechanisms, influencing catalytic activity, selectivity, and stability in CO2 hydrogenation to methanol.

Effect of Al related chemical short-range order on the irradiation resistance of Al0.5CoCrFeNi multi-principal element alloy: A molecular dynamics simulation

Multi-principal element alloys (MPEAs) have received much attention for future nuclear materials due to their exceptional radiation resistance. This work investigated the effect of Al related chemical short-range ordered (CSRO) which caused by its large atomic size in face-centered cubic (FCC) Al0.5CoCrFeNi alloy on its irradiation damage behavior through mixed molecular dynamics and Monte Carlo simulations. The calculation results indicate that the CSRO structure effectively suppresses the generation of point defects during irradiation in Al0.5CoCrFeNi alloy, and this inhibitory effect increases with increasing irradiation energy. The enhanced radiation resistance of CSRO alloy is attributed to the high vacancy formation energy, interstitial atom formation energy, and vacancy migration energy barrier of Al. Moreover, the Al atoms in CSRO alloy can also act as defect barriers, preventing the migration of vacancy defects; The formation energy of interstitial atoms in the CSRO alloy exhibits a strong element dependence, and there is a significant difference in the formation energy of interstitial atoms between different points, which strengthens the hysteresis diffusion effect of MPEAs and further enhances the radiation resistance of MPEAs.