INORGANIC CHEMISTRY
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2019
·
IF 4.85
Mengping He,Dongxing Kou,Wenhui Zhou,Zhengji Zhou,Yuena Meng,Sixin Wu
The earth-abundant Cu2ZnSnS4 (CZTS) quantum dots (QDs) have emerged as one potential substitute to toxic cadmium or rare indium QDs, but their application in quantum dot-sensitized solar cells (QDSSCs) is still limited by the improper particle size and the rigorous synthesis and ligand exchange conditions. Herein, we developed a one-pot hot injection method by using Tri-n-octylphosphine oxide (TOPO) as the solvent and oleylamine as the capping agent to synthesize Cu2ZnSn(S,Se)4 (CZTSSe) QDs with adjustable size and narrow size distribution. The key feature of this approach is that we can take advantage of the high-temperature nucleation, low-temperature growth, and strong reducibility of NaHB4 to prepare small-sized CZTSSe QDs without using 1-dodecanethiol (DDT) and to extend the light harvesting range through Se incorporation. After Se incorporation, it turns out that the conduction band (CB) level of CZTSSe QDs decreases, implying that the injection driving force of the electron to the CB of TiO2 films becomes weaker and a larger recombination would be induced at the TiO2/QDs/electrolyte interface. Benefiting from the broadened optoelectronic response range, the induced higher Jsc (16.80 vs 14.13 mA/cm2) finally leads to the increase of the conversion efficiency of CZTSSe QDSSC from 3.17% to 3.54% without further modification. Despite the fact that the efficiency is still far behind those of literature reported values through use of other chalcogenide sensitizers, this DDT-free approach solves the main hindrance for the application of CZTSSe QDs in QDSSCs and holds a more convenient way for ligand exchange, light absorption improvement, and particle size control.
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ECS Journal of Solid State Science and Technology
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2019
·Vol. 8
·期 5
·P3075
·
IF 1.795
Peng He,Bingbing Wu,Shuai Shao,Tong Teng,Peng Wang,Xin-Ping Qu
Cobalt has been applied as liners in current Cu interconnect and even as interconnect conductors in next-generation interconnect. In this work, effects of corrosion inhibitors 1, 2, 4-triazole (TAZ) on Co chemical corrosion, galvanic corrosion between Cu and Co, and Co polishing properties in the H2O2 based acidic slurry have been systematically investigated. Results show that 5 mM TAZ yields a low static etching and removal rate with a selectivity of about 1: 1 for Co to Cu, applicable for Co barrier/ Cu CMP, while 100 mM TAZ yields a high removal rate with same selectivity, applicable for Co via and trench CMP. It demonstrates that TAZ can effectively inhibit the galvanic corrosion between Co and Cu. Additionally, the adsorption behavior of TAZ on Co surface is both physisorption and chemisorption. In case of 5 mM TAZ, self-assembly TAZ molecules absorb on native Co oxide. In case of 100 mM TAZ, more soluble Co-TAZ complexes form, which reduces the stability of the passivation layer and results in pitting corrosion.
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SOLAR ENERGY MATERIALS AND SOLAR CELLS
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2019
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IF 6.019
Jinming Zeng,Hui Li,Zhijun Wan,Lianghui Ai,Ping Liu,Wenji Deng
Poly(4-vinyltriphenylamine) (PVTPA) was synthesized, and cross-linked poly(4-vinyltriphenylamine) (PVTPA-CL n ) films with a thickness of 260 nm (CL1), 510 nm (CL2), and 680 nm (CL3) were prepared by electropolymerization . Using the PVTPA-CL2 and PVTPA-CL3 films as active materials, the electrochromic devices (ECDs) were fabricated. The structures of the devices were indium tin oxide (ITO) glass/gel electrolyte/PVTPA-CL2/ITO glass (ECD 1) and ITO glass/gel electrolyte/PVTPA-CL3/ITO glass (ECD 2). The electrochromic properties of the PVTPA, PVTPA-CL n films, and ECDs were investigated. Among them, the PVTPA-CL2 and PVTPA-CL3 films exhibited reversible color changes from colorless to gray-green and from colorless to black upon electrochemical doping and dedoping, respectively. The optical contrast of the PVTPA-CL2 and PVTPA-CL3 films were 81.0% and 84.3% at 750 nm, respectively. The ECD 1 could reversibly change between colorless and gray-green under different voltages, and it exhibited 78.3% optical contrast at 750 nm. Notably, ECD 2 could reversibly change between colorless and black under different voltages, and it exhibited 85.0% optical contrast at 750 nm. ECD 1 had shorter switching time than ECD 2, its coloring and bleaching times were 9.5 and 7.3 s, respectively. Both ECD 1 and ECD 2 exhibited reasonable electrochemical cyclic stability.
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JOURNAL OF CHROMATOGRAPHY A
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2019
·
IF 3.858
Chunjian Wu,Li Wang,He Li,Shujuan Yu
The presence of potential carcinogen 4(5)-Methylimidazole (4-MeI) in foods causes much concern, stressing the need of a sensitive determination means. Here, we proposed a high-sensitivity method to determine 4-MeI in biscuits using dansyl chloride derivatization and disperse liquid-liquid micro-extraction (DLLME) followed by a liquid chromatography-ion trap mass spectrometry (LC-IT-MS) analysis. This developed method was subsequently compared to the solid phase extraction combining with liquid chromatography-triple quadrupole mass spectrometry (SPE-LC-QqQ-MS) method. The optimized derivatization conditions were 30 °C and 10 min. Results suggested that the column retention time (RT) was significantly extended, and the MS signal response of 4-MeI-dansyl derivative was also amplified. The developed DLLME-LC-IT-MS method in 4-MeI determination provided satisfactory linearity in a range of 0.5–300 ng/mL (R 2 > 0.9991), inter-day accuracy (87-102%) and precision (%RSD ≤ 13.6%) with the quantification limit of 0.2 ng/mL, which obtained similar results comparing to the conventional SPE-LC-QqQ-MS method.
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NEUROSCIENCE
·
2019
·
IF 3.244
Lanqiu Zhang,Jinlu Zhang,Xiaolin Jiang,Lei Yang,Qi Zhang,Botao Wang,Lihua Cui,Ximo Wang
Neuroinflammation has been implicated in the mechanism underlying the progression of neurodegeneration and infectious neuropathology. Growing evidence suggest that hydroxytyrosol (3,4-dihydroxyphenil-ethanol, HT), one of the main polyphenols presented in extra virgin olive oil (EVOO), has shown potential anti-inflammatory and neuroprotective effects. However, the potential anti-neuroinflammation activity and underlying mechanism of HT remain poorly understood. The present study aimed to investigate the effects of HT on lipopolysaccharide (LPS)-induced inflammation in both in vitro and in vivo models and the associated molecular mechanism. Our results revealed that HT significantly reduced the production of pro-inflammatory mediators in BV2 microglia and primary microglia cells. Phenotypic analysis showed that HT significantly reduced M1 marker CD86 expression and increased M2 marker CD206 expression. In addition, HT significantly decreased the levels of phospho-NF-κB p65 and phospho-extracellular signal-regulated kinase (ERK) in a dose-dependent manner. Moreover, HT suppressed the LPS-induced Toll like receptor 4 (TLR4) in BV2 microglia. In vivo administration of HT following LPS injection significantly reduced some proinflammatory mediator levels and microglia/astrocyte activation in the brain. Together, these results suggest that HT suppressed the LPS-induced neuroinflammatory responses via modulation of microglia M1/M2 polarization and downregulation of TLR-4 mediated NF-κB activation and ERK signaling pathway.
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ChemSusChem
·
2019
·Vol. 12
·期 21
·4791-4798
·
IF 7.804
Xiaohao Liu,Chenguang Wang,Ying Zhang,Yan Qiao,Yang Pan,Longlong Ma
Graphical Linked in to lignin : 4-Alkylphenol is produced selectively over a magnetic Co 1 –Fe 0.1 @NC catalyst from real lignin oil as feedstock, which is obtained by a “lignin-first” strategy from raw biomass. The incorporation of Fe attenuates the adsorption of 4-alkylphenol to the catalyst, which inhibits the further hydrogenation of 4-alkylphenol to 4-alkylcyclohexanol. Lignin valorization to produce high-value chemicals selectively is an enormous challenge in biorefinery. In this study, 4-alkylphenol, formed by breaking the robust C aryl −OCH 3 bonds solely with the retention of other structures in lignin-derived methoxylalkylphenols, was produced selectively over a Co 1 –Fe 0.1 @NC catalyst from real lignin oil as feedstock, which was obtained by a “lignin-first” strategy from either birch or cornstalk. A yield of 64.7 or 88.3 mol % of 4-propylphenol was obtained if birch lignin oil or eugenol was used as the substrate, respectively. The catalysts were characterized by using methods that include Brunauer–Emmett–Teller measurements, XRD, X-ray photoelectron spectroscopy, high-resolution transmission electron microscopy, high-angle annular dark-field scanning transmission electron microscopy, energy-dispersive X-ray spectroscopy, and temperature-programmed desorption with synchrotron vacuum ultraviolet photoionization mass spectrometry. The results of catalyst characterization and comparison experiments indicated that CoN x was the main active phase for demethoxylation and hydrogenation, and the incorporation of Fe weakens the adsorption of 4-propylphenol to the catalyst, which inhibits the excessive hydrogenation of 4-propylphenol. This work shows the potential to produce high-value-added 4-alkylphenol from renewable raw biomass.
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Environmental Science-Nano
·
2019
·Vol. 6
·期 10
·2986-2999
·
IF 7.704
Yuanhong Zhong,Zhi-Feng Chen,Shi-Chao Yan,Wen-Wen Wei,Qianxin Zhang,Guoguang Liu,Zongwei Cai,Lin Yu
Climbazole (CBZ) is an emerging contaminant with adverse effects on aquatic organisms. In this study, a floral array of chromium-substituted magnetite nanoparticles was synthesized, characterized, and used in photocatalytic degradation of CBZ. The results showed that Cr incorporation did not change the spinel structure of magnetite, but resulted in the obvious decrease of its crystallinity. The Cr content greatly influenced the morphology and micro-structure of magnetite nanoparticles, which led to a significantly larger surface area, and more abundant pores and surface hydroxyl groups. Factors such as the UV light source, catalyst concentration, initial level of CBZ, solution pH, peroxymonosulfate (PMS) dosage, and Cr level in magnetite affected the transformation of CBZ. Under the optimized photocatalytic conditions, i.e., 0.2 g L−1 Fe2.52Cr0.48O4, 2.0 μmol L−1 CBZ, 1.0 mmol L−1 PMS, and pH = 3.08, CBZ was almost completely eliminated within 30 min, which was much faster than under photodegradation, biodegradation, or chlorination reported previously. The reactive oxygen species including ˙OH and SO4˙− coexisted and participated in the photocatalytic reaction. The GC-MS analysis revealed the generation of 4-chlorophenol (4-CP) as a primary intermediate following CBZ transformation, based on the stoichiometric relationship between CBZ and 4-CP. The resultant 4-CP in the present study does not increase the risk to aquatic life. The results highlight an environmentally friendly strategy for effective elimination of CBZ.
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FOOD CHEMISTRY
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2018
·
IF 4.946
Chunjian Wu,Li Wang,He Li,Shujuan Yu
The determination of carcinogenic 4(5)-methylimidazole (4-MeI) in complex matrices at trace levels is a challenge because of its higher polarity and weaker column retention capability. Here, we proposed a novel method for the quantification of 4-MeI in various foods and beverages using modified quick, easy, cheap, effective, rugged, and safe (QuEChERS) extraction with liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis. The evaluated QuEChERS extraction with LC-MS/MS method showed excellent linearity (1–200 μg/L, with correlation coefficient (R 2 ) > 0.999), trueness (91–113%), and precision (relative standard deviation (RSD) ≤ 12.3%), but low matrix effect (92–108%) for cola, tea, beer, coffee beverage, bread, biscuit and instant coffee. The expanded measurement uncertainty was less than 34.4% at 95% confidence level. The proposed method can be successfully applied to determine 4-MeI in 28 commercial foods and beverages purchased from local market. Therefore, we believe this method is likely to provide a potential for 4-MeI determination in practical application.
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JOURNAL OF MEMBRANE SCIENCE
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2018
·
IF 6.578
Yuqian Sui,Huayuan Hu,Mitsuru Ueda,Lianjun Wang,Xuan Zhang
In this study, a novel poly[vinyl-(4-benzyl- N , N , N -trimethylammonium bromide) ketone] (QA-PVBK) homopolymer was synthesized by conventional free-radical polymerization, followed by benzyl bromination, and in-situ quaternization reaction, successively. Blend membranes were further constructed between QA-PVBK and commercially available polybenzimidazole (PBI), as novel anion exchange membrane materials. Owing to the short repeating unit of QA-PVBK, the ion-clusters for the ion transport were highly aggregated on the microscale, which significantly contributed to the excellent hydroxide conductivity of the blend membranes. The PBI was introduced as a physical reinforcement, strengthening the membranes’ robustness and suppressing excessive swelling. Membrane PBI/QA-PVBK-OH(70%), with the QA-PVBK-OH (hydroxide form) content of 70% over the entire membrane matrix, exhibited a high hydroxide conductivity of 50.8 mS cm −1 at 60 °C, and, consequently, a good peak power density of 170.6 mW cm −2 at 60 °C/100% relative humidity condition in a H 2 /O 2 single cell test. The blend membranes also demonstrated acceptable chemical stability towards the alkaline condition (1 M NaOH at 60 °C) with the residual conductivity over 59.4% after 168 h. In light of these promising results, the present study demonstrates a facile blending process for simultaneously addressing the ion conductivity and mechanical properties of anion exchange membranes.
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Journal of Materials Chemistry C
·
2018
·Vol. 6
·期 20
·5453-5461
·
IF 5.976
Shaohua Fan,Guojun Gao,Shiyu Sun,Sijun Fan,Hongtao Sun,Lili Hu
Absolute quantum efficiency (QE) of up-conversion (UC) materials is still limited to ∼3%, which strongly limits their applications in many areas. Herein, we report highly efficient UC β-NaYF4:Yb3+,Er3+ micro-cylinders prepared via a newly developed Li+/Na+ ion exchange method (IEM) with absolute QE as high as ∼4.0%. A small amount of Li+ is interstitially incorporated in β-NaYF4:Yb3+,Er3+, which not only maintains well the micro-cylindrical morphology but also enhances the emission intensity by ∼40%, doubles absolute UCQE (∼3.0% under a fixed excitation power density of 15 W cm−2), and prolongs the lifetime. The UC excitation profile is composed of a sharp peak at 976 nm and a weak shoulder at 935 nm. The absolute UCQE of Li+/Na+ IEM β-NaYF4:Yb3+,Er3+ is systemically studied over a wide excitation power density of 0.4–100 W cm−2, and we obtained impressively high UCQE of 4.0% under 60 W cm−2 power density, which is among the highest values in the literature. The application of two green UC emissions of Li+/Na+ IEM β-NaYF4:Yb3+,Er3+ in ratiometric thermometers is successfully demonstrated. The high relative temperature sensitivity (SR) of 1113/T2 and excellent repeatability as indicated by three heating–cooling cycles (293–753 K) suggest their promising application as a temperature sensor.
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Polymer Chemistry
·
2018
·Vol. 9
·期 20
·2785-2796
·
IF 4.927
Lala Rukh Sidra,Guofei Chen,Nafeesa Mushtaq,Kai Ma,Beenish Bashir,Xingzhong Fang
Two asymmetric diamine monomers, incorporating both aryl ether and non-linear benzoxazole groups, namely 5-amino-2-(4-(4-aminophenoxy)phenyl)benzoxazole (p-BOODA) and 5-amino-2-(3-(4-aminophenoxy)phenyl)benzoxazole (m-BOODA), were designed and synthesized. Two novel series of poly(benzoxazole imide)s (PBOIs), PI-3(a–e) and PI-4(a–e), were prepared via thermal imidization of commercial tetracarboxylic dianhydrides with diamines p-BOODA and m-BOODA, respectively. The effects of chain isomerism on molecular packing and the physical properties of PBOIs are investigated. These PBOIs showed excellent mechanical properties with tensile strengths of 106–168 MPa, tensile moduli of 2.7–5.5 GPa and elongations at break of 4.4–9.3%; in addition, they exhibited good thermal stability (T5% = 488–570 °C) and high glass transition temperatures (Tgs) up to 333 °C. Moreover, BTDA (3,3′,4,4′-benzophenone tetracarboxylic dianhydride) derived PBOIs, PI-3b and PI-4b, showed crystalline transition in spite of bent groups and the asymmetric chain structure. The incorporation of the asymmetric benzoxazole structure with flexible ether connecting groups improved the solubility of the PBOI system. Furthermore, the controlled molecular weight (Mw) polymer PI-4e-PA derived from m-BOODA demonstrated excellent solution and melt processability with the lowest complex viscosity of 44 Pa s at 380 °C.
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JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
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2018
·
IF 3.468
Qiang Lu,Xiao-ning Ye,Zhen-xi Zhang,Ze-xiang Wang,Min-shu Cui,Yong-ping Yang
Activated carbon (AC) prepared by physical activation with steam (named as AC-H 2 O) was employed for catalytic fast pyrolysis of bagasse in a hydrogen atmosphere to selectively produce 4-ethyl phenol (4-EP), a valuable phenolic compound. Lab-scale fast pyrolysis experiments were conducted to quantitatively determine the pyrolytic products and investigate several factors on the 4-EP production, including pyrolysis atmosphere, AC type, catalytic pyrolysis temperature, and AC-to-bagasse ratio. The results indicated that the AC-H 2 O (activated by H 2 O) catalyst exhibited much better performance on 4-EP production than other ACs prepared by different activation methods. Compared with the inert atmosphere, the presence of hydrogen atmosphere could significantly promote the 4-EP formation with the yield increase by over 36%. The maximal 4-EP yield of 3.55 wt% with the selectivity of 17.42% was obtained under AC-to-bagasse ratio of 1.5 at 330 °C. In addition, the gas product produced by the pyrolysis process could be recycled to provide a hydrogen atmosphere without an additional hydrogen supply.
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