CRYSTAL GROWTH & DESIGN
·
2015
·
IF 4.891
Hongling Guo,Yong Cui,Qingwen Tian,Shang Gao,Gang Wang,Daocheng Pan
The Cu2ZnSn(S,Se)4 (CZTSSe) has gained extensive attention in thin film solar cells due to their potential as a nontoxic, low-cost, and earth-abundant absorber material, and a rapid increase in power conversion efficiencies has been demonstrated in laboratory. Compared with the most successful hydrazine-based solution process, the nanocrystal-based ink method and non-hydrazine molecular precursor solution approach are more eco-friendly for fabricating high-efficiency CZTSSe solar cells. However, it is hard to obtain a complete large-grain CZTSSe absorber thin film which can facilitate the transport of photogenerated carriers while minimize grain boundary recombination. Here, we present a simple and effective strategy to significantly enhance grain growth of CZTSSe absorber layers by insetting Sb2S3, CuSbS2, and NaSb5S8 thin films. The incorporation of Sb-based thin films can induce grain growth in the selenization process, and did not produce the impurity phase confirmed by XRD patterns and Raman spectra. It was found that the order of the crystal growth promotion ability is Sb2S3 > CuSbS2 > NaSb5S8 under the same experimental conditions. The presented approach can be extended to other solution processes of fabricating CZTSSe solar cells to enhance their microstructural properties, which are critical for applications in CZTSSe absorbers with fine-grain layers.
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ANALYTICAL AND BIOANALYTICAL CHEMISTRY
·
2014
·Vol. 406
·期 28
·7379-7387
·
IF 3.578
Wang Jing,Liu Shu,Ma Bing,Chen Lina,Song Fengrui,Liu Zhiqiang,Liu Chun-ming
Xanthine oxidase (XOD) catalyzes the metabolism of hypoxanthine and xanthine to uric acid, the overproduction of which could cause hyperuricemia, a risk factor for gout. Inhibition of XOD is a major treatment for gout, and biflavonoids have been found to act as XOD-inhibitory compounds. In this study, ultrafiltration liquid chromatography with photodiode-array detection coupled to electrospray-ionization tandem mass spectrometry (UF-LC-PDA–ESI-MS) was used to screen and identify XOD inhibitors from S. tamariscina . High-performance counter-current chromatography (HPCCC) was used to separate and isolate the active constituents of these XOD inhibitors. Furthermore, ultrahigh-performance liquid chromatography (UPLC) and triple-quadrupole mass spectrometry (TQ-MS) was used to determine the XOD-inhibitory activity of the obtained XOD inhibitors, and enzyme kinetics was performed with Lineweaver–Burk (LB) plots using xanthine as the substrate. As a result, two compounds in S. tamariscina were screened as XOD inhibitors: 65.31 mg amentoflavone and 0.76 mg robustaflavone were isolated from approximately 2.5 g S. tamariscina by use of HPCCC. The purities of the two compounds obtained were over 98 % and 95 %, respectively, as determined by high-performance liquid chromatography (HPLC). Lineweaver–Burk plot analysis indicated that amentoflavone and robustaflavone were non-competitive inhibitors of XOD, and the IC
50 values of amentoflavone and robustaflavone for XOD inhibition were 16.26 μg mL −1 (30.22 μmol L −1 ) and 11.98 μg mL −1 (22.27 μmol L −1 ), respectively. The IC
50 value of allopurinol, used as the standard, was 7.49 μg mL −1 (46.23 μmol L −1 ). The results reveal that the method for systematic screening, identification, and isolation of bioactive components in S. tamariscina and for detecting their inhibitory activity using ultrafiltration LC–ESI-MS, HPCCC, and UPLC–TQ-MS is feasible and efficient, and could be expected to extend to screening and separation of other enzyme inhibitors.
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JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
·
2014
·
IF 3.107
Quan-Jin Wu,Qing-Hua Dong,Wei-Jiang Sun,Yan Huang,Qiong-Qiong Wang,Wei-Long Zhou
This study aimed to construct objective and accurate analytical models of tea categories based on their polyphenols and caffeine. A total of 522 tea samples of 4 commonly consumed teas with different fermentation degrees (green tea, white tea, oolong tea, and black tea) were analyzed by high-performance liquid chromatography (HPLC) coupled with spectrophotometry, utilizing ISO 14502, as analytical tools. The content of polyphenols and caffeine varied significantly according to differently fermented teas, indicating that these active constituents may discriminate fermentation degrees effectively. By principal component analysis (PCA) and stepwise linear discriminant analysis (S-LDA), the vast majority of tea samples could be successfully differentiated according to their chemical markers. This study yielded three discriminant functions with the capacity to simultaneously discriminate the four tea categories with a 97.8% correct rate. In classification of oolong and other teas, there were one discriminant function and two equations with best discriminant capacity. Furthermore, the classification of different degrees of fermentation of oolong and external validation achieved the desired results. It is suggested that polyphenols and caffeine are the distinct variables to establish internationally recognized models of teas.
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Scientific Reports
·
2014
·Vol. 4
·期 1
·1-9
·
IF 5.078
Zhong Jie,Xia Zhe,Luo Miao,Zhao Juan,Chen Jie,Wang Liang,Liu Xinsheng,Xue Ding-Jiang,Cheng Yi-Bing,Song Haisheng,Tang Jiang
To obtain high photovoltaic performances for the emerging copper zinc tin sulfide/selenide (CZTSSe) thin film solar cells, much effort has deservedly been placed on CZTSSe phase purification and CZTSSe grain size enhancement. Another highly crucial but less explored factor for device performance is the elemental constitution of CZTSSe surface, which is at the heart of p-n junction where major photogenerated carriers generate and separate. In this work we demonstrate that, despite the well-built phase and large grained films are observed by common phases and morphology characterization (XRD, Raman and SEM), prominent device efficiency variations from short circuited to 6.4% are obtained. Insight study highlights that the surface (0–250 nm) compositions variation results in different bulk defect depths and doping densities in the depletion zone. We propose that suitable sulfurization (at ~10 kPa sulfur pressure) drives optimization of surface constitution by managing the Cu, Zn and Sn diffusion and surface reaction. Therefore, our study reveals that the balance of elemental diffusion and interface reactions is the key to tuning the surface quality CZTSSe film and thus the performance of as resulted devices.
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JOURNAL OF ALLOYS AND COMPOUNDS
·
2015
·
IF 2.999
Yong Cui,Zhe Zhang,Xu Du,Wei Liu,Yulin Deng,Shi Liu,Gang Wang
Ternary metastable wurtzite structure Cu 2 SnS 3 nanocrystals were successfully synthesized via solvothermal way. As-synthesized Cu 2 SnS 3 nanocrystals were characterized in detail by X-ray powder diffraction, energy dispersive X-ray spectrometry, UV–Vis–NIR spectrometry and transmission electron microscopy . Hybrid solution has been obtained by mixing Cu 2 SnS 3 nanocrystals ink and Zn molecule precursor solution. Hybrid solution process was used to fabricate Cu 2 ZnSn(S,Se) 4 thin film .
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HIGH PERFORMANCE POLYMERS
·
2015
·
IF 1.286
Yewei Xu,Yi Sun,Yonglin Lei,Jichuan Huo,Lin Zhang
This article presents a convenient polymerization route to synthesize poly(arylene ether)s containing N-arylenebenzimidazolyl groups. The novel polymers were prepared by a catalyst-free nucleophilic substitution reaction, in which the N–H and O–H sites were removed from 2-(2-hydroxyphenyl)-1H-benzimidazole with different activated difluorides containing carbonyl groups in sulfolane. The reaction was carried out in the presence of anhydrous potassium carbonate at 210°C. The structures of the polymers were characterized using Fourier transform infrared spectroscopy, proton nuclear magnetic resonance spectroscopy, and elemental analysis. The results show good agreement with the proposed structure. All resulting polymers show essentially amorphous patterns. Moreover, differential scanning calorimetry and thermogravimetric measurements show that the polymers have high glass transition temperatures (>209°C), good thermostability, and high decomposition temperatures (>425°C). Furthermore, the polymers also exhibit excellent solubility in common organic solvents.
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ANALYTICA CHIMICA ACTA
·
2015
·
IF 4.513
Wenjing Lu,Xiaojuan Gong,Ming Nan,Yang Liu,Shaomin Shuang,Chuan Dong
A facile and eco-friendly approach to prepare nitrogen(N)- and sulfur(S)-doped carbon dots (CDs) by one step microwave-assisted pyrolysis of the precursors with dl -malic acid as carbon source, ethanolamine and ethane-sulfonic acid as N and S dopants, respectively, was reported. Through the extensive investigation on morphology, chemical structures and optical properties of the carbon dots, it was found that the obtained CDs exhibited good luminescence stability, high resistance to photo bleaching and favorite solubility. Compared with undoped CDs, adding the N or S dopant could give rise to a slightly smaller particle size and a long fluorescence lifetime of CDs. Moreover, the optimal N-CDs was successfully employed as good multicolor cell imaging probes due to its fine dispersion in water, excitation-dependent emission, excellent biocompatibility and low toxicity. Besides, such N-CDs showed a wide detection range and excellent accuracy as fluorescent probe for Fe 3+ ions. This probe enabled the selective detection of Fe 3+ ions with a linear range of 6.0–200 μM and a limit of detection of 0.80 μM.
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Inorganic Chemistry Frontiers
·
2017
·Vol. 5
·期 1
·258-265
·
IF 4.036
Lili Tan,Yanhong Liu,Baodong Mao,Bifu Luo,Guan Gong,Yuanzhi Hong,Biyi Chen,Weidong Shi
The development of single-component photocatalysts with narrow bandgaps (2.0–3.0 eV) has been one of the most important goals for photocatalytic H2 production, for which I–III–VI multinary sulfides play an important role due to their widely tunable composition-dependent bandgap. However, simultaneous bandgap narrowing and photocatalytic activity enhancement in the I–III–VI sulfides are often difficult to achieve due to increased defect states. Here, a series of Cu–In–Zn–S quantum dots (QDs) were synthesized by a facile hydrothermal method focusing on a more profound understanding of bandgap tuning and the subsequent effect on the photocatalytic process by controlling the Cu content. The bandgap of the QDs can be effectively tuned from 2.90 eV to 1.98 eV with an increasing Cu : In ratio from 0.05 : 10 to 2.5 : 10 and a color change from light yellow to dark red. The QDs show photocatalytic H2 production activity even without any cocatalyst, but it quickly starts to decrease with the Cu/In ratio over 0.1 : 10 (bandgap of 2.59 eV), which highly limits the potential for visible light photocatalysis. Interestingly, Pt-loading effectively enhanced not only the tolerance of Cu incorporation, but also enabled a high H2 production activity even with further bandgap narrowing down to ∼2 eV. The best photocatalytic performance of 456.4 μmol h−1 g−1 was achieved for the Cu : In : Zn ratio of 1 : 10 : 5 with a bandgap of 2.27 eV. This increased tolerance of Cu content may result from a combined effect of charge separation by Pt as the cocatalyst that alleviated the Cu-induced charge recombination. The enhanced charge separation was proved by the photoluminescence quenching of the QDs with the cocatalyst. Electrochemical impedance spectroscopy was further used to study the charge separation properties of this photocatalytic system. This is the first observation of the cocatalyst-enhanced tolerance of Cu resulting from the competition of cocatalyst-induced charge separation and defect-induced charge recombination in multinary sulfides, which provides an interesting view and design guideline for the development of narrow bandgap photocatalysts.
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Polymer Chemistry
·
2017
·Vol. 8
·期 37
·5749-5760
·
IF 5.375
Hongcan Zhang,Jian Zhang,Wenxue Dai,Youliang Zhao
The simple and straightforward construction of multi-responsive systems with tunable LCST and UCST dual phase transitions is a great challenge. This study affords an efficient route to tune cloud points via control over the chemical composition of hydroxyl and diethylamino bearing poly(amido thioether)s which were prepared by one-pot thiol–amine–acrylate polyaddition. Owing to the balance of inter/intrachain interactions, various copolymers could exhibit LCST (fOH < 0.84), LCST–UCST (fOH = 0.84–0.89) and UCST (fOH > 0.89) behaviors relying on the hydroxyl fraction in comonomer units. Meanwhile, the thermoresponsive behaviors of copolymer solutions could be efficiently tuned via switching the solvent and solution pH, applying CO2/N2 bubbling, and oxidation. The success of this study further paves the way for the robust synthesis and practical applications of smart polymers with double thermoresponsivity.
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RSC Advances
·
2016
·Vol. 6
·期 96
·94014-94023
·
IF 3.289
Di Zhang,Min Wang,Xiaoli Liu,Jinsheng Zhao
Two novel electrochromic copolymers, poly(benzodithiophene-benzotriazole) (PBDBT) and poly(s-indacenodithiophene-benzotriazole) (PIDBT) were synthesized successfully through Stille coupling reactions. Both polymers were characterized by cyclic voltammetry (CV), UV-Vis spectroscopy, density functional theory (DFT), colorimetry and thermal gravimetric analysis. The band gaps of the two polymers calculated according to spectroelectrochemistry data are 1.90 eV for PBDBT and 1.93 eV for PIDBT, respectively. The PBDBT film turns rosybrown to transparent grey when it is oxidized and the PIDBT film turns pale violet-red in the neutral state to transparent light grey in the oxidized state. PBDBT has an 55.0% optical contrast at 1500 nm, PIDBT has an 60.8% optical contrast at 1560 nm, and their corresponding response times are 1.49 s and 1.85 s, respectively. In addition, the coloration efficiency of PBDBT at 1500 nm is 144.70 cm2 C−1, and the coloration efficiency of PIDBT at 1560 nm is 222.00 cm2 C−1. Both copolymers demonstrate good properties, and can be promising electrochromic materials for commercial applications.
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JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY
·
2017
·Vol. 55
·期 8
·1313-1321
·
IF 2.952
Ying Chen,Yanping Tao,Jinlei Wang,Shanzhong Yang,Sheng Cheng,Haibing Wei,Yunsheng Ding
A series of poly(ether sulfone)-based anion exchange membranes (AEMs), tethering with guanidinium side chains with different spacers, were synthesized via azide-alkyne cycloaddition, deprotection, and the subsequent ion exchange reactions. The designed polymer structures were verified by the 1 H NMR spectra. Because of the appropriate water uptake and formation of interconnected ionic clusters, the GPES-3C with propyl spacer showed higher conductivity than the GPES-1C and GPES-9C, with methylene and nonyl spacers, respectively. Comparatively, the GPES-EO AEM with two ethylene oxide (EO) spacers exhibited even higher conductivity, these can be interpreted by interconnectivity of ionic channels and hydrophilicity nature of the EO spacer. Additionally, although the GPES membranes displayed sufficient thermal stability, the chemical stability of as-prepared materials needs to be much improved for fuel cell applications. Overall, these results demonstrated that the properties of “pendent-type” AEM can be tuned facilely by the spacer types and lengths. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55 , 1313–1321
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JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY
·
2017
·Vol. 55
·期 12
·2092-2103
·
IF 2.952
Yi Xiao,Hui-Qing Wang,Hao Zhang,Zhi-Qiang Jiang,Ya-Qi Wang,Hai Li,Jun Yin,Yuan-Yuan Zhu,Zong-Quan Wu
We herein report a “grafting from” strategy to immobilize optically active helical poly(phenyl isocyanide)s onto graphene oxide (GO) nanosheets. After covalently bounding alkyne-Pd(II) initiator onto GO nanosheets, the designed GO/polymer composites P1 @GO and P1 - b - P2 @GO featuring single-handed helical poly(phenyl isocyanide)s growing from GO nanosheets were prepared by sequential addition of the chiral and achiral isocyanide monomers. Post-synthetic hydrolysis rendered P1 - b - P3 @GO to improve the hydrophilicity. The successful covalent bonding of poly(phenyl isocyanide)s chains onto GO nanosheets was certified by several cross evidences including scan emission microscopy, atomic force microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, and thermogravimetric analysis. Circular dichroism spectra proved that the chiral information was introduced through the grafted single-handed helical polymer chains successfully. In addition, the resulting GO/polymer composites were explored as a chiral additive to induce enantioselective crystallization of racemic organic molecules. Preferential formation of rod-like L -alanine crystals was induced by composites bearing right-handed helical poly(phenyl isocyanide)s. The enantiomeric excess value of the induced crystals reached 76%, displaying the potential in future applications. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55 , 2092–2103
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