Co-reporter:Da-peng Wang;Mu-quan Yang;Zhi-xin Dong;Shu-qin Bo
Chinese Journal of Polymer Science 2013 Volume 31( Issue 9) pp:1290-1298
Publication Date(Web):2013 September
DOI:10.1007/s10118-013-1321-9
A mixed system that includes poly(ethylene oxide) (PEO) and silica (SiO2) nanoparticles is prepared using two mixing methods. The interaction between PEO and the SiO2 nanoparticles in the dilute basic solution is investigated using the dynamic light scattering (DLS) and isothermal titration calorimetry (ITC) techniques. The DLS results show qualitatively that SiO2 nanoparticles interact with both random coils and aggregates of PEO through hydrogen bonding, and PEO-SiO2 complexes are formed. The degree of disaggregation of aggregates of PEO is readily adjusted by changing the concentration of SiO2 nanoparticle suspensions. Moreover, the ITC results also certify quantitatively the interaction between PEO and SiO2 nanoparticle, and give the evidence of formation of PEO-SiO2 complex.
Co-reporter:Na-na Zhao;Wei Nie;Jun Mao;Wei-cai Wang
Chinese Journal of Polymer Science 2013 Volume 31( Issue 9) pp:1233-1241
Publication Date(Web):2013 September
DOI:10.1007/s10118-013-1318-4
A facile route to synthesize a new type of multifunctional nanocomposites is reported. Here, PDMAEMA (poly[2-(dimethylamino)ethyl] methacrylate) is a key macromolecule serving as a bridge between magnetic Fe2O3 nanoparticles and luminescent quantum dots. Both Fe2O3 nanoparticles and II–VI semiconductor quantum dots with a narrow size distribution are synthesized through a two-phase thermal approach. Subsequently, the atom transfer radical polymerization (ATRP) technique was applied to prepare magnetic Fe2O3@PDMAEMA core-shell nanoparticles. The thickness of PDMAEMA shell can be easily controlled by adjusting the reaction time. Finally, the ligand exchange method was exploited to modify II-VI quantum dot with amine-containing polymer of PDMAEMA, which led to quantum dot securely bound by Fe2O3@PDMAEMA core-shell nanoparticle to form a multifunctional nanocomposite. The resulting nanocomposite remains variable emission by tuning the II–VI semiconductor type and particle size and shows Hc at 49 kA/m and Tb at 16 K from Fe2O3 nanoparticles. The self-assembled behavior for the resulting samples is also discussed.
Co-reporter:Guihua Liu;Xuepeng Qiu;Shuqin Bo
Chromatographia 2012 Volume 75( Issue 1-2) pp:7-15
Publication Date(Web):2012 January
DOI:10.1007/s10337-011-2159-3
Chain conformation and local rigidity of two isomerized polyimides (PIs), poly(6FDA/3,3′-DMB) and poly(6FDA/2,2′-DMB) in dimethyl formamide (DMF) with either 0.1 M LiBr or 3.1 mM tetrabutylammonium bromide at 35 °C, are investigated. Size exclusion chromatography (SEC) coupled with multi-angle laser light scattering detector, viscometer, and differential refractive index detector was used. The scaling exponents α and ν related to conformation are estimated from the above results. The values of α and ν for poly(6FDA/3,3′-DMB) are 0.68 ± 0.01 and 0.54–0.55 ± 0.01, respectively. The values of α and ν for poly(6FDA/2,2′-DMB) are 0.65 ± 0.02 and 0.55 ± 0.01, respectively, which indicate that both PIs in DMF have a random coil conformation. In particular, poly(6FDA/3,3′-DMB) exhibits more extended conformation than that of poly(6FDA/2,2′-DMB). Parameters related to chain flexibility of polymers, including persistence length lp, shift factor ML (relative molecular weight per unit contour length), and backbone diameter d are evaluated from the relationship between intrinsic viscosity and molecular weight based on the wormlike continuous cylinder model. The three parameters (lp, ML, and d) indicate that the two samples are flexible chains with local rigidity, and poly(6FDA/3,3′-DMB) is slightly stiffer than poly(6FDA/2,2′-DMB). In addition, influence of salt types on the parameters is also discussed.
Co-reporter:Muquan Yang;Jun Mao;Wei Nie;Zhixin Dong;Dapeng Wang;Ziliang Zhao
Journal of Polymer Science Part A: Polymer Chemistry 2012 Volume 50( Issue 10) pp:2075-2083
Publication Date(Web):
DOI:10.1002/pola.25985
Abstract
We present herein a mild and rapid method to create diblock copolymer brushes on a silicon surface via photoinitiated “thiol-ene” click reaction. The silicon surface was modified with 3-mercaptopropyltrimethoxysilane (MPTMS) self-assembled monolayer. Then, a mixture of divinyl-terminated polydimethylsiloxane (PDMS) and photoinitiator was spin-coated on the MPTMS surface and exposed to UV-light. Thereafter, a mixture of thiol-terminated polyethylene glycol (PEG) and photoinitiator were spin-coated on the vinyl-terminated PDMS-treated surface, and the sequent photopolymerization was carried out under UV-irradiation. The MPTMS, PDMS, and PEG layers were carefully identified by X-ray photoelectron spectroscopy, atomic force microscopy, ellipsometry, and water contact angle measurements. The thickness of the polydimethylsiloxane-block-poly(ethylene glycol) (PDMS-b-PEG) diblock copolymer brush could be controlled by the irradiation time. The responsive behavior of diblock copolymer brushes treated in different solvents was also discussed. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012
Co-reporter:Zhixin Dong, Hua Wei, Jun Mao, Dapeng Wang, Muquan Yang, Shuqin Bo, Xiangling Ji
Polymer 2012 Volume 53(Issue 10) pp:2074-2084
Publication Date(Web):25 April 2012
DOI:10.1016/j.polymer.2012.03.011
Poly(N,N-dimethylaminoethyl methacrylate) (PDMAEMA) was grafted onto the surface of silica nanoparticles via surface-initiated atom transfer radical polymerization to form temperature- and pH-responsive PDMAEMA brushes (silica-g-PDMAEMA). The resultant samples were characterized via 1H NMR, transmission electron microscopy, atomic force microscopy, Fourier transform infrared spectroscopy, and thermogravimetric analysis. Their molecular weights and molecular weight distributions were determined by gel permeation chromatography analysis after silica content etching. The control of brush thickness and the responsive behavior were systematically investigated. Dynamic light scattering (DLS) results indicate that the brush thickness can be controlled by changing the polymerization time and the DMAEMA, initiator, and THF concentrations. According to DLS and zeta potential results, the lower critical solution temperature (LCST) of the PDMAEMA brushes shifts to a higher temperature with decreasing solution pH, which is attributed to the weak charge of the polyelectrolyte brushes. When the temperature is kept above the transition temperature, the silica-g-PDMAEMA nanoparticles aggregate into clusters and disaggregate during the cooling process. Moreover, with the heating/cooling step increasing, the aggregation and disaggregation temperatures are decreased. Meanwhile, when the molecular weight is increased from 13.6 × 104 to 23.1 × 104 g/mol, a decrease in the LCSTs at constant pH is observed. The related properties of the corresponding quaternized analog, poly{[2-(methacryloyloxy)ethyl] trimethylammonium iodide} (PMETAI) brushes, were also discussed. The hydrodynamic radius of the silica-g-PMETAI nanoparticles decreases with increasing ionic strength, and a salting-out/salting-in effect is observed when the ionic strength is adjusted using NaI instead of NaCl.
Co-reporter:Qinghui Liu, Zechen Zhao, Yuhan Lin, Peng Guo, Shenjie Li, Daocheng Pan and Xiangling Ji
Chemical Communications 2011 vol. 47(Issue 3) pp:964-966
Publication Date(Web):15 Nov 2010
DOI:10.1039/C0CC03560B
Cu2SnS3
nanocrystals with metastable zincblende and wurtzite structures have been successfully synthesized for the first time. Alloyed (ZnS)x(Cu2SnS3)1−x and (CuInS2)x(Cu2SnS3)1−x nanocrystals with arbitrary composition (0 ≤ x ≤ 1) and ultra-broad tunable band gaps (3.63 to 0.94 eV) were obtained.
Co-reporter:Yanhu Xue, Yandi Fan, Shuqin Bo, Xiangling Ji
European Polymer Journal 2011 Volume 47(Issue 8) pp:1646-1653
Publication Date(Web):August 2011
DOI:10.1016/j.eurpolymj.2011.05.016
Two polypropylene alloys (Samples A and B), as impact polypropylene (PP) with similar ethylene contents and melt indices but different impact properties at low temperatures, are fractionated into eight fractions using preparative temperature rising elution fractionation. The microstructure of the original samples and their fractions are studied using high-temperature gel permeation chromatography, Fourier transform infrared spectroscopy, 13C nuclear magnetic resonance spectroscopy, and differential scanning calorimetry. The results indicate that the two alloys are mainly composed of four portions: ethylene–propylene random copolymer (EPR), ethylene–propylene segmented copolymer, ethylene–propylene block copolymer, and propylene homopolymer. Sample A contains more EPR and more fractions with higher isotacticity eluted at 120 and 140 °C than Sample B. The difference in the microstructure distributions of both PP alloys results in observable differences in their mechanical properties: Sample A has better impact toughness and possesses higher rigidity than Sample B. Sample A also exhibits better balance between toughness and stiffness.Three-dimensional surface plots can be achieved from cross-fractionation results obtained by combining TREF and GPC data, as shown in figures. Each region on the 3D surface gives the relative amount of each species with a given molecular weight and composition. The 3D surfaces show clear structural features of both samples and the minimal difference in their microstructure distributions.
Co-reporter:Jun Mao;Shuqin Bo
Macromolecular Chemistry and Physics 2011 Volume 212( Issue 7) pp:744-752
Publication Date(Web):
DOI:10.1002/macp.201000672
Co-reporter:Jun Mao, Shuqin Bo, and Xiangling Ji
Langmuir 2011 Volume 27(Issue 12) pp:7385-7391
Publication Date(Web):May 18, 2011
DOI:10.1021/la201287t
The pH- and temperature-responsive behavior of amphiphilic block copolymer poly(l-lactide)-b-poly(2-(dimethylamino)ethyl methacrylate) (PLLA-b-PDMAEMA) in aqueous solutions is investigated using static and dynamic light scattering. Electrostatic force, hydrophobic interaction, and hydrogen bonding coexist in the system. Micelles with different structures are prepared using water addition (WA) and direct dissolution (DD) methods. The aggregation from loose micelles into large micellar clusters is observed above the transition temperature under basic conditions. Only micellar clusters from the DD method could disaggregate when temperature was decreased to 24.3 °C after heating. The behavior of the micelles prepared with the DD method indicates that only the outer parts of the PLLA-b-PDMAEMA chains in the corona are solvated.
Co-reporter:Zhixin Dong, Jun Mao, Muquan Yang, Dapeng Wang, Shuqin Bo, and Xiangling Ji
Langmuir 2011 Volume 27(Issue 24) pp:15282-15291
Publication Date(Web):November 7, 2011
DOI:10.1021/la2038558
Biocompatible and zwitterionic poly(sulfobetaine methacrylate) (PSBMA) was grafted onto the surface of initiator-modified silica nanoparticles via surface-initiated atom transfer radical polymerization. The resultant samples were characterized via nuclear magnetic resonance, Fourier transform infrared spectroscopy, transmission electron microscopy, and thermogravimetric analysis. Their molecular weights and molecular weight distributions were determined via gel permeation chromatography after the removal of silica by etching. Moreover, the phase behavior of these polyzwitterionic-grafted silica nanoparticles in aqueous solutions and stability in protein/PBS solutions were systematically investigated. Dynamic light scattering and UV–visible spectroscopy results indicate that the silica-g-PSBMA nanoparticles exhibit an upper critical solution temperature (UCST) in aqueous solutions, which can be controlled by varying the PSBMA molecular weight, ionic strength, silica-g-PSBMA nanoparticle concentration, and solvent polarity. The UCSTs shift toward high temperatures with increasing PSBMA molecular weight and silica-g-PSBMA nanoparticle concentration. However, increasing the ionic strength and solvent polarity leads to a lowering of the UCSTs. The silica-g-PSBMA nanoparticles are stable for at least 72 h in both negative and positive protein/PBS solutions at 37 °C. The current study is crucial for the translation of polyzwitterionic solution behavior to surfaces to exploit their diverse properties in the development of new, smart, and responsive coatings.
Co-reporter:Yandi Fan, Chunyu Zhang, Yanhu Xue, Xuequan Zhang, Xiangling Ji, Shuqin Bo
Polymer 2011 Volume 52(Issue 2) pp:557-563
Publication Date(Web):21 January 2011
DOI:10.1016/j.polymer.2010.12.009
Two polypropylene homopolymers, samples A and B, synthesized with heterogeneous Ziegler–Natta catalysts, are studied in this work. Both samples show improved impact properties at low temperature than isotactic PP. Particularly, sample B exhibits better toughness, higher molecular weight and slight lower flexural properties than sample A. Then, these two samples were fractionated into six fractions via temperature rising dissolution fractionation, respectively. Both samples are mainly composed of fractions 4, 5 and 6, which were collected above 100 °C and have high isotacticity. On the one hand, the fractions of sample B have higher molecular weight than the corresponding fractions of sample A collected at the same temperatures. On the other hand, 13C NMR and DSC analyses of the fractions indicate clearly that fractions of sample B have lower isotacticity and crystallinity than the corresponding fractions of sample A. The above difference in microstructure between samples A and B should be the key factors resulting in their difference in mechanical properties finally. Both polypropylene homopolymers possibly become new type of impact PP.
Co-reporter:Guiyan Zhao;Yongfeng Men;Zhonghua Wu;Wei Jiang
Journal of Polymer Science Part B: Polymer Physics 2010 Volume 48( Issue 2) pp:220-225
Publication Date(Web):
DOI:10.1002/polb.21851
Abstract
The effect of shear on the crystallization behavior of the poly(ether ether ketone) (PEEK) has been investigated by means of ex situ wide-angle X-ray diffraction (WAXD), small-angle X-ray scattering, and differential scanning calorimetry (DSC). The changes of the intensity of WAXD patterns along shear direction of the PEEK induced by short-term shear were observed when the samples crystallized at 330 °C. The results showed that the dimensions of the crystallites perpendicular to the (110) and (111) planes reduced with the increase of shear rate, whereas the dimensions of the crystallites perpendicular to (200) plane increased with the increase of shear rate. Moreover, increasing shear rate can lead to the increase of the crystallinity as well as the average thickness of the crystalline layers. Correspondingly, a new melting peak at higher temperature was found during the subsequent DSC scanning when the shear rate was increased to 30 s−1. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 220–225, 2010
Co-reporter:Haidong Li, Wei Nie, Chao Deng, Xuesi Chen, Xiangling Ji
European Polymer Journal 2009 Volume 45(Issue 1) pp:123-130
Publication Date(Web):January 2009
DOI:10.1016/j.eurpolymj.2008.10.008
Crystalline morphologies of spin-coated poly(l-lactic acid) (PLLA) thin films under different conditions are investigated mainly with atomic force microscopy (AFM) technique. When PLLA concentration in chloroform is varied from 0.01 to 1% gradually, disordered structure, rod-shape and larger spheres aggregates are observed in thin films subsequently. Under different annealing temperature, such as at 78, 102, 122 °C, respectively, we can find most rod-like crystalline aggregates. Interestingly, we observed that nucleation sites locate at the edge of the holes at the original crystalline stage. Then, these holes developed to form chrysanthemum-like and rods subsequently with annealing time meanwhile the size and the shape of crystalline aggregate are changed. In addition, effect of substrate and solvent on morphology is also discussed. On the other hand, the possible mechanism of crystalline morphology evolution is proposed.
Co-reporter:Yandi Fan, Chunyu Zhang, Yanhu Xue, Wei Nie, Xuequan Zhang, Xiangling Ji and Shuqin Bo
Polymer Journal 2009 41(12) pp:1098-1104
Publication Date(Web):October 9, 2009
DOI:10.1295/polymj.PJ2009150
Three Polypropylene/Poly(ethylene-co-propylene) (PP/EPR) in-reactor alloys produced by a two-stage slurry/gas polymerization had different ethylene contents and mechanical properties, which were achieved by controlling the copolymerization time. The three alloys were fractionated into five fractions via temperature rising dissolution fractionation (TRDF), respectively. The chain structures of the whole samples and their fractions were analyzed using high-temperature gel permeation chromatography (GPC), Fourier transform infrared (FT-IR), 13C nuclear magnetic resonance (13C NMR), and differential scanning calorimetry (DSC) techniques. These three in-reactor alloys mainly contained four portions: ethylene-propylene random copolymer (EPR), ethylene-propylene (EP) segmented and block copolymers, and propylene homopolymer. The increased copolymerization time caused the increased ethylene content of the sample. The weight percent of EPR, EP segmented and block copolymer also became higher. The more EPR content indeed improves the toughness of the alloy but lowers its stiffness. Increasing the ethylene content in the EPR fraction and EP segmented and block copolymer, as well as the suitable content of EPR, is believed to be the key factors resulting in the excellent toughness-stiffness balance of in-reactor alloys.
Co-reporter:Yandi Fan, Yanhu Xue, Wei Nie, Xiangling JI and Shuqin Bo
Polymer Journal 2009 41(8) pp:622-628
Publication Date(Web):June 17, 2009
DOI:10.1295/polymj.PJ2009030
In this work, two industrial bimodal high density polyethylene resins, resin A and resin B, having similar molecular weight (Mw), molecular weight distribution (MWD, and short-chain branching (SCB) content but different mechanical properties, were fractionated through cross-fractionation. The fractions were further characterized by GPC, 13C NMR, DSC and FT-IR techniques. These two resins were firstly fractionated into two fractions, i.e., high-temperature and low-temperature fractions, via preparative solution crystallization fractionation. Resin A with much better mechanical properties contains more high-temperature fractions with longer crystallizable sequences. The SCB content in the low-temperature fraction of resin A is lower than that of resin B. Both low-temperature fractions were then further fractionated using solvent gradient fractionation (SGF). The characterization of SGF fractions indicates that most of the branches fall into the high molecular weight chains in both low-temperature fractions. However, the high molecular weight chains in the low-temperature fraction of resin A contain less SCB than that of resin B.
Co-reporter:Yuhan Lin, Haidong Li, Changpeng Liu, Wei Xing, Xiangling Ji
Journal of Power Sources 2008 Volume 185(Issue 2) pp:904-908
Publication Date(Web):1 December 2008
DOI:10.1016/j.jpowsour.2008.08.067
In this study, Nafion® 117 membrane is surface-modified with mesoporous silica layers through in situ surfactant-templated sol–gel reaction. The reaction makes use of tetraethyl orthosilicate (TEOS) under acidic condition via dip-coating technique on both sides. Scanning electron microscopy (SEM), Fourier transformation infrared (FTIR), and thermogravimetric analysis (TGA) are employed to characterize the resultant membranes. Proton conductivity and methanol permeability of the membranes are also studied. It is determined that the aging time, along with the number of the silicon dioxide (SiO2) layer, influence both proton conductivity and methanol permeability. Specifically, double-side modified membrane with 5 min interval of the second layer (S (5)) exhibits optimal properties on the combined criterion of conductivity and permeability. However, the application of mesoporous silica layer in modifying commercial Nafion membranes through dip-coating is proven to be a facile route in improving the said criteria simultaneously.
Co-reporter:Pengchang Ma;Wei Nie;Zhenghua Yang;Peihong Zhang;Gang Li;Qingquan Lei;Lianxun Gao;Mengxian Ding
Journal of Applied Polymer Science 2008 Volume 108( Issue 2) pp:705-712
Publication Date(Web):
DOI:10.1002/app.27540
Abstract
A sol–gel process has been developed to prepare polyimide (PI)/Al2O3 hybrid films with different contents of Al2O3 based on pyromellitic dianhydride (PMDA) and 4,4′-oxydianiline (ODA) as monomers. FESEM and TEM images indicated that Al2O3 particles are relatively well dispersed in the polyimide matrix after ultrasonic treatment of the sol from aluminum isopropoxide and thermal imidization of the gel film. The dimensional stability, thermal stability, mechanical properties of hybrid PI films were improved obviously by an addition of adequate Al2O3 content, whereas, dielectric property and the elongation at break decreased with the increase of Al2O3 content. Surprisingly, the corona-resistance property of hybrid film was improved greatly with increasing Al2O3 content within certain range as compared with pure PI film. Especially, the hybrid film with 15 wt % of Al2O3 content exhibited obviously enhanced corona-resistance property, which was explained by the formation of compact Al2O3 network in hybrid film. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Co-reporter:Peng Han, Hongming Zhang, Xuepeng Qiu, Xiangling Ji, Lianxun Gao
Journal of Molecular Catalysis A: Chemical 2008 Volume 295(1–2) pp:57-67
Publication Date(Web):12 November 2008
DOI:10.1016/j.molcata.2008.08.016
Initially, pore walls of mesoporous silica SBA-15 with template were modified with chlorotrimethylsilane. Then imidazolium salts were similarly incorporated covalently in the inner pore walls of mesoporous silica SBA-15 albeit without the template. Finally, palladium salts were introduced into the pore channels of the previously processed mesoporous silica via electrostatic interaction. The resulting palladium catalysts demonstrated exceptional activity for the room-temperature Suzuki coupling reaction in aqueous-organic mixed solvents and good recycling ability for at least 4–6 times. The turnover frequency of resulting catalysts could reach up to 84,000 h−1 at 50 °C. The corresponding samples were analyzed with solid-state NMR, FT-IR, XRD, nitrogen adsorption–desorption isotherms, TEM and XPS techniques. In addition, agglomeration of palladium catalyst in the Suzuki coupling reaction can be effectively controlled due to the stabilizing effect of the imidazulium salt and confinement of mesoporous walls.Palladium salts were introduced into the pore channels of the imidazolium salts-functionalized mesoporous silica SBA-15 via electrostatic interaction. The resulting palladium catalysts demonstrated exceptional activity for the room-temperature Suzuki coupling reaction in aqueous-organic mixed solvents and good recycling ability. In addition, agglomeration of palladium catalyst in the Suzuki coupling reaction can be effectively controlled due to the stabilizing effect of the imidazulium salt and confinement of mesoporous walls.
Co-reporter:Yuhan Lin, Nana Zhao, Wei Nie and Xiangling Ji
The Journal of Physical Chemistry C 2008 Volume 112(Issue 42) pp:16219-16224
Publication Date(Web):2017-2-22
DOI:10.1021/jp803782u
Dissolvable, size- and shape-controlled ruthenium dioxide nanoparticles are successfully achieved through a two-phase route. The influence of reaction time, temperature, and monomer concentration and the nature of capping agents on the morphologies of nanoparticles are studied through transmission electron microscopy (TEM). A possible mechanism for the formation and growth of nanoparticles is also involved. X-ray powder diffraction (XRD) confirms the amorphous structure for as-prepared ruthenium dioxide nanoparticles. Samples are immobilized by simple dip-coating on a current collector, and the cyclic voltammetry measurement is utilized to investigate their electrochemical properties. The specific capacitance of one sample can reach as high as 840 F g−1, which reveals the promising application potential to electrochemical capacitors.
Co-reporter:D. Pan;N. Zhao;Q. Wang;S. Jiang;X. Ji;L. An
Advanced Materials 2005 Volume 17(Issue 16) pp:
Publication Date(Web):30 JUN 2005
DOI:10.1002/adma.200500479
A simple, two-phase approach using an autoclave is taken to synthesize high-quality anatase TiO2 nanocrystals with a narrow size distribution (see Figure). The size-tunable luminescence of the TiO2 nanocrystals is dominated by band-edge luminescence at room temperature. The nanocrystals could be readily dispersed in toluene after capping with stearic or oleic acid.
Co-reporter:D. Pan;Q. Wang;S. Jiang;X. Ji;L. An
Advanced Materials 2005 Volume 17(Issue 2) pp:
Publication Date(Web):25 JAN 2005
DOI:10.1002/adma.200401425
An environmentally harmless method of synthesizing extremely small CdSe and highly luminescent CdSe/CdS core–shell quantum dots (see Figure) with CdSe cores of 1.2–1.5 nm diameter is reported. The CdSe/CdS core–shell quantum dots exhibit 60–80 % quantum yield at room temperature. The emission peak is tunable from 445 to 517 nm (purplish blue to green yellow) by increasing the diameter of the CdSe core and/or the thickness of the CdS shell.
Co-reporter:Qiang Wang;Daocheng Pan;Shichun Jiang Dr. ;Lijia An ;Bingzheng Jiang
Chemistry - A European Journal 2005 Volume 11(Issue 13) pp:
Publication Date(Web):13 APR 2005
DOI:10.1002/chem.200400993
A new two-phase route has been developed to synthesize high-quality CdS nanocrystals with a narrow size distribution and a high photoluminescence (PL) quantum yield (QY). In the two-phase system, toluene and water were used as separate solvents for cadmium myristate (CdM2) and thiourea, which served as cadmium source and sulfur source, respectively, and oleic acid (OA) was used as a ligand for stabilizing the nanocrystals. The reactions were completed in the heated autoclaves. The initial Cd/S molar ratio of the precursors and the reaction temperature were found to be factors that affected the growth of nanocrystals. Furthermore, a seeding-growth technique was developed to synthesize CdS nanocrystals of different sizes, which exhibit PL peaks with quite similar full width at half-maximum (FWHM) values compared to those of the initial nanocrystal seeds in all cases.
Co-reporter:Qinghui Liu, Zechen Zhao, Yuhan Lin, Peng Guo, Shenjie Li, Daocheng Pan and Xiangling Ji
Chemical Communications 2011 - vol. 47(Issue 3) pp:NaN966-966
Publication Date(Web):2010/11/15
DOI:10.1039/C0CC03560B
Cu2SnS3
nanocrystals with metastable zincblende and wurtzite structures have been successfully synthesized for the first time. Alloyed (ZnS)x(Cu2SnS3)1−x and (CuInS2)x(Cu2SnS3)1−x nanocrystals with arbitrary composition (0 ≤ x ≤ 1) and ultra-broad tunable band gaps (3.63 to 0.94 eV) were obtained.
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ioxo-2H-isoindole-5,2-diyl)[2,2'-bis(trifluoromethyl)[1,1'-biphenyl]-4,4'-di
yl]]](http://img.cochemist.com/ccimg/129300/129219-41-6.png)
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ioxo-2H-isoindole-5,2-diyl)[2,2'-bis(trifluoromethyl)[1,1'-biphenyl]-4,4'-di
yl]]](http://img.cochemist.com/ccimg/129300/129219-41-6_b.png)
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