JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2017
·
IF 3.454
Qilai Zhou,Yasuhisa Oya,Takumi Chikada,Wen Zhang,Lihong Xue,Youwei Yan
Ultrafine lithium titanate (Li 2 TiO 3 ) powder was synthesized by hydrothermal method . The phase formation and transition condition among α, β, and γ-Li 2 TiO 3 were discussed. XRD and ICP-AES showed the single α-phase was formed at 180 °C with 2 h hydrothermal reaction, and it transited into β-phase at 400 °C. SEM observation and EDS analysis confirmed the dissolution of TiO 2 and the formation of α-Li 2 TiO 3 proceeded simultaneously with preferable growth direction of (-133) lattice. During the phase transition, the powder maintained the small crystallite , which facilitated the fabrication of Li 2 TiO 3 bulk with small grain size. After the Ar + irradiation, the surface region to the depth of 3 μm of Li 2 TiO 3 ceramic was affected, where the decrease of crystallization and disturbance of short-range order were confirmed by GIXRD and Raman spectroscopy . In spite of the structure change at the surface area, the ceramic bulk maintained the same.
研究领域:
材料科学
·
核能工程
✓ 已验证
产品关联
DOI
高影响因子
MACROMOLECULES
·
2024
·
IF 5.1
Jianfei Xia,Lingling Ni,Chang Zeng,Bao Wang,Rui Zhang,Chenxuan Sun,Jian Song,Junfeng Liu,Chengtao Yu,Ying Zheng,Pengju Pan
Terephthalic polyesters are important engineering plastics and can crystallize into multiple crystal phases, including the mesophase in processing. However, the formation process and structural characteristics for the unique long-range ordered mesophase of terephthalic polyesters are still not well understood. Herein, we investigated the crystal polymorphism, crystallization kinetics, phase transition, and mechanical properties of a medium-chain terephthalic polyester, poly(hexamethylene terephthalate) (PHT). A new long-range ordered mesophase (named as the δ phase) is discovered for PHT during quiescent melt crystallization at a low crystallization temperature (Tc = 10–30 °C). However, the α and β crystal phases are crystallized at a medium (40–80 °C) and high (90–130 °C) Tc, respectively. The mesomorphic δ phase has a long-range order with a layered structure and inclined chain packing, which shows faster chain relaxation and smaller lamellar thickness than the α and β phases. The mesomorphic δ phase is metastable and converts into the stable β phase upon heating or high-temperature annealing. Mechanical properties of PHT can be well tuned by crystal polymorphs. The mesomorphic δ phase of PHT has good transparency and ductility, while the α and β phases possess a higher yield strength and modulus. This work provides an in-depth understanding of the mesophase formation and complex crystal polymorphism of terephthalic polyesters.
研究领域:
材料科学
·
高分子化学
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2025
·
IF 5.6
Chengzhi Xu,Lei Yang,Jieliang Su,Jianping Zhang,Jiakai Cao,Xiaodong Li,Gang He,Zhanggui Hu
Silicon nitride (Si 3 N 4 ) with α -phase content ∼90.0 wt% and oxygen content ∼1.00 wt% was prepared by combustion synthesis method using recycled silicon waste from photovoltaic industry. The effects of reaction pressure and environmentally-friendly new additive C 3 H 6 N 6 on the phase composition, and morphology and reaction mechanism of the combustion synthesized α -Si 3 N 4 powder were studied. The results indicate that a lower N 2 pressure is conducive to increasing the α -phase content and reducing the oxygen content of the Si 3 N 4 powder. The addition of C 3 H 6 N 6 as an effective additive facilitates the deoxidation and nitridation reactions of recycled silicon waste, which further increases the α -phase content and reduces the oxygen content of the Si 3 N 4 powder. This work demonstrated that the recycled silicon waste from photovoltaic industry holds great promise to be used as the silicon source for the cost-effective synthesis of high quality α -Si 3 N 4 powder.
研究领域:
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2025
·
IF 5.6
Jiale Zhang,Jianjun Chen,Jinyu Guo,Hao Chen,Longbo Xue,Chenyu Li
In this study, silicon nitride (Si 3 N 4 ) powders with high α-phase content and rod-like crystal morphologies were synthesized via self-propagating high-temperature synthesis (SHS) in a low-pressure nitrogen atmosphere (0.2 MPa), using silicon and Si 3 N 4 powders as reactants, with magnesium powder serving as an igniter. The influence of different ratios of silicon to silicon nitride on the phase composition, crystal morphology, and sintering activity of the synthesized Si 3 N 4 powders was systematically investigated. The results demonstrated that controlling the silicon-to-silicon nitride ratio under low-pressure conditions significantly affects the formation of α-phase Si 3 N 4 and the resulting microstructure of the powders. A low-pressure nitrogen atmosphere was adopted based on kinetic and thermodynamic analyses, providing a feasible environment for SHS. Notably, in situ formation of magnesium nitride (MgSiN 2 ) during the reaction not only acted as an effective sintering aid but also improved the thermal conductivity of the resulting Si 3 N 4 ceramic. The powder produced from a reaction using a raw material composition of 65% Si minimizes both silicon infiltration and melting to the greatest extent, and consequently, the sintered silicon nitride ceramics exhibit the highest thermal conductivity. The low-pressure environment effectively moderated the reaction rate and temperature, promoting the formation of fine α-phase Si 3 N 4 particles with rod-like morphologies. This innovative method offers a cost-effective and environmentally friendly approach for producing high-quality Si 3 N 4 powders with high sintering activity.
研究领域:
材料科学
·
陶瓷工程
✓ 已验证
产品关联
DOI
高影响因子
Joule
·
2022
·
IF 46.048
Lingfeng Chao,Yingdong Xia,Xiaozheng Duan,Yue Wang,Chenxin Ran,Tingting Niu,Lei Gu,Deli Li,Jianfei Hu,Xingyu Gao,Jing Zhang,Yonghua Chen
Direct and stable α-phase formation of formamidinium lead triiodide (FAPbI 3 ) perovskite serves as an indispensable prerequisite for constructing stable and efficient perovskite solar cells. However, the α-phase formation is highly limited by molecular additives. Here, we report a strategy for directly fabricating stable α-phase of FAPbI 3 perovskite by controlling the precursor solution on the molecular level using methylammonium acetate (MAAc) ionic liquid. We found that a strong interaction between Ac − and Pb 2+ via C=O···Pb chelation enables the relaxation of Pb–I bonds and thus allows the effective insertion of formamidinium iodide (FAI) into soft Pb–I framework. Molecular dynamics simulations also show that the precursor solution has undergone an exchange of coordination between I − and Ac − to provide the reaction sites for FAI. With a one-step, antisolvent-treatment-free, and air-processing approach regardless of humidity, the corresponding photovoltaic cell exhibits an efficiency close to 24% along with long operational stability over 1,000 h.
研究领域:
材料科学
·
能源技术
·
化学工程
✓ 已验证
DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2023
·
IF 5.7
Binwei Huang,Pingzhan Si,Quanxing Ren,Zhuang Qian,Ziqiang Yin,Zhengren Huang,Qing Huang,Yinsheng Li
SiC ceramic was fabricated by spark plasma sintering of β-SiC powder and Y 2 O 3 -MgO additives in argon. The effects of β→α phase transformation of SiC on microstructure and thermal conductivity of densified bulks were systematically investigated, in comparison to the counterparts using α-SiC as starting powder. The β→α phase transformation led to a “unimodal to bimodal” transition in grain size distribution. After sintering at 1850 o C, the incomplete β→α phase transformation induced the appearance of β/α heterophase boundary with strong effect of phonon-scattering. After sintering at 2050 o C, the completion of β→α phase transformation resulted in enlarged grains and disappearance of β/α heterophase boundary in SiC ceramic. The lattice oxygen content was decreased primarily by enhanced grain growth and oxygen picking-up of sintering additives, and possibly some contribution from β→α phase transformation. The optimized microstructure enabled SiC ceramic to obtain a remarkable increase in thermal conductivity from 126 to 204 W/mK after the replacement of α-SiC by β-SiC as starting powder and the accomplishment of β→α phase transformation.
研究领域:
材料科学
·
热物理
✓ 已验证
产品关联
DOI
高影响因子
ENVIRONMENT INTERNATIONAL
·
2025
·
IF 9.7
Mingshu Li,Fuchang Deng,Li Dong,Xiaona Wang,Haiyan Jiang,Siyu Yao,Yuanyuan Chen,Lian Duan,Huamao Du,Guangqiu Qin,Song Tang
Aluminum oxide (Al 2 O 3 ) nanoparticles (NPs) are extensively utilized in the food industry for applications such as food packaging, antimicrobial coatings, food processing equipment, and additives. Despite their widespread use, the mechanisms underlying Al 2 O 3 NP-induced hepatotoxicity and the relationship between their physicochemical properties and toxicity remain inadequately understood. In this study, we explored the hepatotoxic effects of α -Al 2 O 3 and γ -Al 2 O 3 NPs in rats subjected to oral exposure for 28 days. Employing an integrated metabolomics and microbiome approach, we aimed to elucidate the potential mechanisms involved. Our findings revealed distinct hepatotoxic profiles for α -Al 2 O 3 and γ -Al 2 O 3 NPs, potentially mediated by differential interactions with the intestinal microbiome. α -Al 2 O 3 NPs exhibited reduced hepatotoxicity, as evidenced by minimal liver oxidative stress, which may be associated with the upregulation of digestion-related intestinal flora such as Peptococcaceae and Romboutsia , potentially influencing Al 2 O 3 accumulation in the liver. Conversely, γ -Al 2 O 3 NPs demonstrated pronounced hepatotoxicity, characterized by liver histopathological changes and elevated levels of alanine aminotransferase, malondialdehyde, and glutathione. This increased toxicity was correlated with alterations in intestinal flora, including Ruminococcaceae and Exiguobacterium , which affected metabolites like L-phenylalanine and arachidonic acid, potentially contributing to hepatotoxicity. The results underscore the importance of the intestinal microbiome in mediating NP-induced toxicity and determining differences in toxicities of different NP phases. This study provides valuable insights into the differential toxicological impacts of Al 2 O 3 NP phases, paving the way for safer nanomaterial design and application in the food industry.
研究领域:
毒理学
·
纳米生物学
·
食品科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF CHEMICAL PHYSICS
·
2022
·Vol. 157
·期 19
·
IF 4.304
Xu Tie,Cai Hongkun,Ye Xiaofang,Zhu Yinbin,Ni Jian,Li Juan,Zhang Jianjun
Black-phase formamidinium lead iodide (FAPbI 3 ), with a narrow bandgap and high thermal stability, has emerged as an in-demand material for highly efficient perovskite solar cells (PSCs). In a two-step sequential deposition, the PbI 2 film plays an important role in the formation of a perovskite film with desirable qualities. This paper explores using N-methyl-2-pyrrolidone (NMP), a strong Lewis base, and N,N-dimethylformamide (DMF) as a mixed precursor solvent (DMF/NMP) of PbI 2 and reports on preparing PbI 2 films with a porous morphology by thermal treatment. Porous PbI 2 films ensure the diffusion and sufficient reaction of the formamidinium iodide solution to form a smooth perovskite film. In addition, a dynamic spin coating method is also introduced to improve the uniformity of the perovskite film. Both methods yield a pure α-phase FAPbI 3 film immediately in the unannealed state, which is necessary for the perovskite film to maintain phase stability. Finally, PSCs with a power conversion efficiency of 21.20% (0.13 cm 2 ) are fabricated and optimized. The unencapsulated PSCs retain 90% of the initial efficiency for 1000 hours in dry air and exhibit a good thermal stability when heated to 85 °C.
研究领域:
材料科学
·
能源技术
·
光伏器件
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Advanced Science
·
2025
·Vol. 12
·期 14
·2407401
·
IF 14.1
Qianyi Li,Dongyang Li,Zhiqi Li,Qiong Liang,Patrick W. K. Fong,Yu Han,Kuan Liu,Jiangsheng Yu,Peng Bai,Tao Zhu,Yang Bai,Guang Yang,Zhiwei Ren,Gang Li
Hybrid metal halide perovskite solar cells (PSCs) are emerging as highly competitive next-generation photovoltaics due to their excellent performance and low production cost. However, the construction of high-efficiency PSCs typically requires an inert nitrogen environment within a glove box, inadvertently increasing manufacturing costs and hindering the transition from lab-scale to industrial-scale production. In this work, an air ambient fabrication of pure α-phase FAPbI 3 PSCs with high-efficiency and stability, utilizing a dual-functional engineering strategy assisted by 3-Guanidinopropionicacid (3-GuA) is reported. 3-GuA assists in managing excess PbI 2 and promotes the formation of high-quality FAPbI 3 films via intermolecular exchange. Simultaneously, the existence of 3-GuA minimizes the defects and stabilizes the resulting perovskite films. As a result, the ambient-air fabricated PSCs achieve a power conversion efficiency (PCE) of 24.2% with negligible hysteresis and excellent stability. Additionally, these devices demonstrate superior reproducibility, offering valuable guidance for future advancements in this technology.
研究领域:
材料科学
·
光伏技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Catalysts
·
2020
·Vol. 10
·期 1
·119
·
IF 3.52
Yuyang Wei,Wenbin Zhang
Nickel electrodes under continuous potential cycling were applied for the electrooxidation of benzyl alcohol and glycine in KOH solutions, and their activities were measured and compared by cyclic voltammetry. It is shown that intrinsic activities of both reactions decrease with the increasing catalyst loadings, and a more significant decreasing trend was observed in glycine electrooxidation when compared to benzyl alcohol electrooxidation. These phenomena may be explained by an increasing of mass loading induced a decrease of the catalyst surface conductivity, structure changes of Ni(OH)2from α-phase to β-phase, and the intercalation of glycine molecules into nickel hydroxide interlayers.
研究领域:
电化学
·
催化
·
材料科学
✓ 已验证
DOI
高影响因子
ADVANCED MATERIALS
·
2019
·Vol. 31
·期 25
·1901284
·
IF 25.809
Minchao Qin,Kinfai Tse,Tsz-Ki Lau,Yuhao Li,Chun-Jen Su,Guang Yang,Jiehuan Chen,Junyi Zhu,U-Ser Jeng,Gang Li,Hongzheng Chen,Xinhui Lu
Mixed perovskites have achieved substantial successes in boosting solar cell efficiency, but the complicated perovskite crystal formation pathway remains mysterious. Here, the detailed crystallization process of mixed perovskites (FA 0.83 MA 0.17 Pb(I 0.83 Br 0.17 ) 3 ) during spin-coating is revealed by in situ grazing-incidence wide-angle X-ray scattering measurements, and three phase-formation stages are identified: I) precursor solution; II) hexagonal δ-phase (2H); and III) complex phases including hexagonal polytypes (4H, 6H), MAI–PbI 2 –DMSO intermediate phases, and perovskite α-phase. The correlated device performance and ex situ characterizations suggest the existence of an “annealing window” covering the duration of stage II. The spin-coated film should be annealed within the annealing window to avoid the formation of hexagonal polytypes during the perovskite crystallization process, thus achieving a good device performance. Remarkably, the crystallization pathway can be manipulated by incorporating Cs + ions in mixed perovskites. Combined with density functional theory calculations, the perovskite system with sufficient Cs + will bypass the formation of secondary phases in stage III by promoting the formation of α-phase both kinetically and thermodynamically, thereby significantly extending the annealing window. This study provides underlying reasons of the time sensitivity of fabricating mixed-perovskite devices and insightful guidelines for manipulating the perovskite crystallization pathways toward higher performance.
研究领域:
材料科学
·
光伏技术
·
晶体学
·
薄膜制备
·
X射线散射
✓ 已验证
DOI
高影响因子
Nature Photonics
·
2020
·Vol. 15
·期 3
·238-244
·
IF 31.241
Chen Jiawei,Wang Jian,Xu Xiaobao,Li Jinhang,Song Jizhong,Lan Si,Liu Sinan,Cai Bo,Han Boning,Precht Jake T.,Ginger David,Zeng Haibo
At present, electric lighting accounts for ~15% of global power consumption and thus the adoption of efficient, low-cost lighting technologies is important. Halide perovskites have been shown to be good emitters of pure red, green and blue light, but an efficient source of broadband white electroluminescence suitable for lighting applications is desirable. Here, we report a white light-emitting diode (LED) strategy based on solution-processed heterophase halide perovskites that, unlike GaN white LEDs, feature only one broadband emissive layer and no phosphor. Our LEDs operate with a peak luminance of 12,200 cd m −2 at a bias of 6.6 V and a maximum external quantum efficiency of 6.5% at a current density of 8.3 mA cm −2 . Systematic in situ and ex situ characterizations reveal that the mechanism of efficient electroluminescence is charge injection into the α phase of CsPbI 3 , α to δ charge transfer and α–δ balanced radiative recombination. Future advances in fabrication technology and mechanistic understanding should lead to further improvements in device efficiency and luminance.
研究领域:
材料科学
·
光电技术
·
半导体物理
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）