NEW JOURNAL OF CHEMISTRY
·
2013
·Vol. 38
·期 1
·448-454
·
IF 2.966
Lai-Jun Zhang,Xing-Can Shen,Hong Liang,Fa-Yun Chen,Hai-Jin Huang
ZnSe:Mn and core–shell ZnSe:Mn/ZnS doped quantum dots (d-dots) have been synthesized by using the alkylamine–H2Se complex and thiourea as new phosphine-free Se and S precursors, respectively. Absorption spectroscopy, steady-state (solution and solid-state) and time-resolved photoluminescence spectroscopy, energy-dispersive X-ray spectroscopy, and transmission electron microscopy were used to characterize the resulting d-dots. Results showed that Mn2+ was successfully doped and mainly distributed in the middle layer of the actual ZnSe/ZnSe:Mn/ZnSe d-dots and ZnSe/ZnSeS:Mn/ZnS d-dots which were simply referred to as ZnSe:Mn and core–shell ZnSe:Mn/ZnS d-dots with ZnSe and ZnS outmost shells, respectively. The increase in the intensity of phosphorescence from the dopant Mn2+ was obtained by the corresponding injection of Zn precursor or Zn/S precursors for ZnSe or ZnS shell growth. As compared to the ZnSe shell, the ZnS shell was grown more significantly on the surface of the ZnSe:Mn core, which led to larger d-dots due to a thicker ZnS shell and thus deeper doping of Mn2+ in the larger host. Outstanding improvement has been achieved in both phosphorescence intensity and stability after growth of the ZnS shell relative to the ZnSe shell. The corresponding phosphorescence efficiency of the resulting d-dot cyclohexane solution was enhanced from about 8% for the ZnSe:Mn d-dots to 35% for the ZnSe:Mn/ZnS d-dots.
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2023
·
IF 3.9
Zhe Zhao,Cheng Han,Xiaozhou Wang,Yingde Wang
Metallopolymers containing refractory metal in the main chain are highly desired but rarely reported as oxygen-free single-source precursors for preparing ultrahigh-temperature ceramics. Herein, a novel single-source precursor of poly-hafnium-borocarbosilane (PHBCNS) with an Hf–N–B backbone molecular structure was synthesized through the dehalogenation reaction between HfCl 4 and B(NHCH 3 ) 3 . The polymeric Hf–N–B chain with large bond angle and conjugated molecular structure endowed the PHBCNS precursor to be relatively stable, dissolvable, and meltable. Subsequent precursor pyrolysis up to 1800°C resulted in an HfC/HfB 2 nanocomposite comprising an Hf content of 87.54 wt%, with the average grain size of HfC and HfB2 to be 34.9 and 74.1 nm, respectively. The ceramization mechanism and phase evolution from the PHBCNS precursor to HfC/HfB 2 composite ceramics were thoroughly investigated. This work not only highlights a novel Hf–N–B backbone polymer with high metal content and good shaping properties but also provides fresh insights of designing single-source precursors for ultrahigh-temperature composite ceramics.
研究领域:
材料科学
·
无机化学
✓ 已验证
产品关联
DOI
高影响因子
Energy Technology
·
2018
·Vol. 7
·期 5
·1800734
·
IF 3.175
Jian Cheng,Qinqin Xu,Jiangteng Lu,Jiehao Du,Qin Chen,Yanmei Zhang,Zaiquan Li,Feng He,Fuzhong Wu,Haibo Xie
Carbon materials with a high specific surface area, large pore size, high electrical conductivity, and high chemical stability are regarded as promising electrode materials for supercapacitors. With the advantages of using ionic liquids precursors and biomass-based precursors for the synthesis of carbon materials, nitrogen-doped porous activated carbon materials with an ultrahigh surface area (up to 3638 m 2 g −1 ), a desirable pore size (up to 2.44 nm), and a high content of 10.38 at % oxygen and 1.14 at % nitrogen are prepared from alginic-based protic polyanion ionic liquids (APPILs) using the KOH activation method. The specific structural properties of the as-prepared carbon materials can be tuned by the nature of organic bases in the APPILs and carbonization conditions. When used as electrode materials for symmetric supercapacitors in 6 m KOH electrolytes, the obtained carbon material shows a significantly high gravimetric capacitance of up to 354 F g −1 at a current density of 0.1 A g −1 . Moreover, the assembled supercapacitor delivers a relatively high energy density of 12.3 W h kg −1 and a power density of 26 W kg −1 , as well as a high cycling stability of 95% capacitance retention after 10 000 cycles.
研究领域:
材料科学
·
能源科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2025
·
IF 6.3
Fangfang Wu,Xiaohui Tan,Wuzhi Zhu,Xiuxun Han
At present, most reported solution-processed highly efficient Cu 2 ZnSn(S,Se) 4 (CZTSSe) solar cells are prepared from precursor solutions with sulfur-containing complexing agents. However, the organic solutions with sulfur-containing groups are generally toxic and always produce harmful gases during pyrolysis. From the view of environment protection and process safety, preparing CZTSSe from the oxide precursor is more favorable for the application and development of CZTSSe photovoltaic technology compared with the sulfide precursor route. In this work, we developed a sulfur-free solution method for preparing CZTSe solar cells based on a monoethanolamine-ethanol blend wherein the ethanolamine serves as both complexing agent and reducing agent. The precursor thin film prepared is mainly composed of amorphous oxides and a small amount of copper. We found that the content of ethanolamine not only affects the formation of copper-rich phase on the surface of the precursor film, but also affects the formation of zinc-rich phase on the surface of the absorber layer. By systematically investigating the effects of ethanolamine content on precursors, absorbers and solar cells, an oxide precursor route to preparing CZTSe solar cells based on solution with low ethanolamine content and two-step drying process was successfully proposed.
研究领域:
材料科学
·
太阳能技术
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MATERIALS ENGINEERING AND PERFORMANCE
·
2025
·
IF 2
Jiao Hua,Wang Qingxiang,Wang Jia,Zhao Kang,Qinggong Jia
ZrC and TiC are high-temperature materials that can be used in astronautic and aeronautic industries. Titanium (Ti) and zirconium (Zr) belong to adjacent elements of the same IVB family; their similar chemical properties can form a relatively stable crystal structure. Zr x Ti 1-x C composite ceramics doped with Ti were prepared by precursor pyrolysis method. The precursor of aqueous solution systems is more environmentally friendly than in organic systems. The results show that preparing high-purity Zr x Ti 1-x C composite ceramics can be obtained at the Zr: C and Ti: C molar ratio more than 1: 4. The mole number of C is at least four times than the metal ions Zr 4+ or Ti 4+ . The maximum phase transformation temperature is 502.3 °C in Zr 0.25 Ti 0.75 C, which is significantly higher than the initial oxidation temperature 460 °C of ZrC. The result indicates that the Zr x Ti 1-x C composite ceramics reinforced by Ti have better oxidation resistance than pure ZrC ceramics. The crystal structure and bonding properties, electronic characteristics, phonon dispersion spectrum and dynamic stability, mechanical property, and thermodynamic properties of Zr x Ti 1-x C are calculated using first principles showing that Zr 0.25 Ti 0.75 C is the best material.
研究领域:
材料科学
·
无机非金属材料
·
计算材料学
·
高温结构材料
·
陶瓷材料
✓ 已验证
产品关联
DOI
高影响因子
Nanomaterials
·
2023
·Vol. 13
·期 7
·1189
·
IF 5.3
Qingtao Li,Qi Cai,Xiaoyun Li,Enshan Han,Yanmin Sun,Yanfei Lu,Zhe Cai,Haibin Yu
To screen a suitable precursor, the effects of palladium salts on performance of Pd nanocatalysts for the oxidation of volatile organic components (VOCs) were investigated. A series of catalysts was prepared by impregnating Pd(NO3)2, PdCl2and Pd(NH3)4Cl2on alumina-coated cordierites. These catalysts were characterized by XRF, ICP-OES, XRD, N2adsorption-desorption, TEM, EDS, Raman spectroscopy, pulse-CO chemisorption, H2-TPR, NH3-TPD, and XPS. Pulse-CO chemisorption and TEM showed that Pd species formed by Pd(NO3)2have the highest metal dispersion (17.7%), while the other two were aggregating. For the same Pd loading, the higher the metal dispersion, the more the number of PdO species, so the number of PdO particles in the catalyst prepared from Pd (NO3)2is the largest. The catalytic oxidation activities of these catalysts were evaluated by ethane and propane. Based on a 99% conversion in the oxidation of ethane and propane at 598 K and 583 K, respectively, the catalyst prepared from Pd(NO3)2was considered to be the best performing catalyst. The chloride species in precursors can promote the aggregation of Pd species and poison the catalysts. The results show that Pd(NO3)2is more suitable as the precursor of VOC oxidation catalyst than PdCl2and Pd(NH3)4Cl2.Keywords:volatile organic components;palladium;catalytic oxidation;precursors
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Physical Chemistry C
·
2016
·
IF 4.509
Fei Li,Zhiguo Xia,Quanlin Liu
Controlled synthesis of absorber materials Cu2ZnGeS4 (CZGS) has been performed using different Ge precursors, including GeCl4 and the self-synthesized Ge complexes with Ge-glycolic acid (denoted as Ge-Gly), Ge-tartaric acid (denoted as Ge-Tar), and Ge-citric acid (denoted as Ge-Cit). The grain size of as-prepared CZGS nanocrystals (NCs) is dependent on the Ge precursors. All four Ge precursors enabled the wurtzstannite CZGS phase formation. The Ge-Cit precursor led to the formation of monodispersed NCs owing to the fact that the undissolved metal-Cit complex in OLA absorbed the small CZSG NCs and avoided the irregular crystalline behavior. The other three precursors induced two different sizes, and the corresponding reaction mechanism has been proposed. Moreover, the Cu2ZnGe1–xSnxS4 NCs with different Ge/Sn ratios were prepared using the Ge-Cit precursor, verifying the general effect on the phase formation and selective grain sizes. The compositional effect on the band gap variation and morphologies of Cu2ZnGe1–xSnxS4 was also studied.
研究领域:
材料科学
·
化学合成
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2025
·
IF 6.2
Fahai Dong,Nannan Zhu,Zhongya Zhang,Jiawei Jiang,Juhai Weng,Lijuan Zhang
This study successfully synthesized a novel SiCN ceramic precursor with high photosensitivity and ceramic yield through the addition reaction of Si-H and N-H groups in polysilazane (PSZ) with isocyanate groups in 2-isocyanoethyl methacrylate (IEM). The reaction mechanism between IEM and PSZ, and the curing and pyrolysis effects were investigated. The results showed that compared with 5 s exposure time, PSZ could not be cured, while the curing depth of PSZ could reach 1.51 mm after adding IEM chemical grafting modification, which significantly improved the curing printing efficiency. Increasing IEM content to 10 wt% reduced cure shrinkage from 13.85 % to 12.56 %, with a ceramic yield of 79.92 %. The bending strength of SiCN ceramic reached 30.7 MPa, and the microstructure of pyrolyzed samples was dense and free of defects. This research expands the application field of 3D-printed SiCN ceramics.
研究领域:
材料科学
·
高分子化学
·
陶瓷工程
✓ 已验证
DOI
高影响因子
ZEITSCHRIFT FUR ANORGANISCHE UND ALLGEMEINE CHEMIE
·
2024
·
IF 1.1
Ting Chen,Hanzi Du,Ralf Riedel,Zhaoju Yu
This work successfully fabricated a novel CNWs/Ni 2 Si/SiOC nanocomposite ceramic material using a single-source-precursor derived ceramic approach. The material exhibits in-situ formation of carbon nanowires (CNWs) and multiple core-shell nanoparticles such as Ni 2 Si@C and SiC@C. The reaction mechanism of the precursor, the microstructure and phase composition, and the ceramics′ electromagnetic wave (EMW) absorbing properties were thoroughly investigated and discussed. The obtained CNWs/Ni 2 Si/SiOC nanocomposite ceramics possesses a minimum reflection loss (RLmin) of −43.5 dB, indicating excellent EMW absorbing performance. The in-situ formation of CNWs and multi-core-shell nanoparticles (Ni 2 Si@C and SiC@C) in the ceramics play a crucial role in enhancing their EMW absorbing properties compared to pure SiOC ceramics.
研究领域:
材料科学
·
电磁学
✓ 已验证
产品关联
DOI
高影响因子
POLYMER INTERNATIONAL
·
2015
·Vol. 64
·期 8
·979-985
·
IF 2.409
Lijuan He,Zongbo Zhang,Xiaogan Yang,Lingling Jiao,Yongming Li,Caihong Xu
A series of liquid polycarbosilanes were successfully synthesized by a sequential Grignard coupling reaction of (chloromethyl)triethoxysilane and vinylmagnesium bromide, followed by reduction with lithium aluminium hydride. The use of non-corrosive, easily handleable and storage stable (chloromethyl)triethoxysilane as starting material is an attractive advantage for this route. The as-synthesized polymers containing Si−CH=CH 2 and Si − H groups are storage stable and can be easily cured in an inert atmosphere. The ceramic yield of the cured polycarbosilane and the C:Si ratio of the derived ceramic were varied by adjusting the mole ratio of starting materials in the feed. Among them, the polymer with a mole ratio of Si−CH=CH 2 to Si − H of 1:10 has the highest ceramic yield at 89.6% after curing at 220 °C and the C:Si ratio of the derived ceramic is 1.48. This kind of polycarbosilane shows high potential as an SiC ceramic precursor in the fabrication of an SiC matrix by the precursor infiltration pyrolysis process. © 2015 Society of Chemical Industry
研究领域:
材料科学
·
化学工程
·
无机化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF SOLID STATE ELECTROCHEMISTRY
·
2022
·Vol. 26
·期 6
·1359-1368
·
IF 2.747
Chen Renhong,Mei Jie,Xu Jin,Xu Wanjie,Wang Laisen,Chen Yuanzhi,Peng Dong-Liang
High-voltage LiNi 0.5 Mn 1.5 O 4 with a spinel structure is considered as important cathode materials for high-energy density Li-ion batteries (LIBs). In this study, we investigate the size, structure, and the electrochemical performance of LiNi 0.5 Mn 1.5 O 4 electrodes prepared by using two different-sized Mn 3 O 4 nanocrystal precursors under different calcination conditions. As the calcination temperature rises, the particle sizes of the acquired LiNi 0.5 Mn 1.5 O 4 cathode materials can vary from ~ 100 nm to ~ 1 µm, and the morphology changes from nano round shape to truncated octahedral shape. The content of Mn 3+ is closely related to the calcination temperature and is affected by the size of Mn precursor. It is found that the LiNi 0.5 Mn 1.5 O 4 sample prepared by using 50-nm-sized Mn 3 O 4 nanocrystals under a calcination temperature of 800 C exhibits good cycling performance with a capacity retention ratio of 96.1% at 1 C after 200 cycles, while the LiNi 0.5 Mn 1.5 O 4 sample prepared by using 7-nm-sized Mn 3 O 4 nanocrystals under a calcination temperature of 800 °C shows an excellent rate performance with a capacity retention ratio of 98% after 500 cycles at 10 C. The results show that the size of Mn 3 O 4 precursor is an important parameter that governs the final size and electrochemical performances of LiNi 0.5 Mn 1.5 O 4 cathode materials.
研究领域:
材料科学
·
能源科学
✓ 已验证
DOI
高影响因子
Journal of Materials Chemistry C
·
2020
·Vol. 8
·期 7
·2436-2441
·
IF 7.059
Li Jiang,Yuwei Li,Jiali Peng,Lihao Cui,Ruiming Li,Yalun Xu,Wei Li,Yanyan Li,Xiaoyu Tian,Qianqian Lin
Chalcogenides have attracted great attention in the past few decades because of their excellent processability and outstanding optoelectronic properties. Particularly, AgBiS2 has been the frontier of the photovoltaic field in the past few years. AgBiS2 possesses fascinating merits, such as a high absorption coefficient, suitable bandgap, decent charge transport properties and superior material stability. However, most of the efficient AgBiS2-based devices are fabricated with AgBiS2 quantum dots, which require long fabrication time and complicated synthetic steps. Moreover, most of the reports focused on photovoltaic devices, and AgBiS2-based photodetectors have not been reported yet. Based on the challenges listed above, we developed AgBiS2 photodetectors based on a molecular precursor method with a p–i–n device structure. These photodetectors exhibited broadband spectral response with decent detectivity and fast response time of 700 ns. In addition, these devices also demonstrated outstanding air, light and water stability.
研究领域:
材料科学
·
光电子学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）