JOURNAL OF NANOPARTICLE RESEARCH
·
2013
·Vol. 15
·期 8
·1-11
·
IF 2.175
Zhang Qiang,Cao Yongqiang,Shen Jianxing,Yang Ping
Nearly monodisperse CdSe/CdS and CdSe/Cd
x
Zn 1− x
S core–shell quantum dots (QDs) were synthesized by the epitaxial growth of CdS or Cd
x
Zn 1– x
S shells on pre-synthesized CdSe cores through a facile organic route. The thickness effect of CdS and Cd
x
Zn 1− x
S shells on the properties of resulting core–shell QDs, such as the photoluminescence (PL) efficiency, PL full width at half-maximum (fwhm), and PL decay lifetime, were investigated. The PL efficiency is greatly enhanced from 9 % of CdSe cores to 64 % of CdSe/Cd
x
Zn 1− x
S core–shell QDs. The PL spectra are narrowed after coating (fwhm ~28–32 nm). The alloy Cd
x
Zn 1− x
S shell is especially effective to enhance the PL efficiency, and it leads to a smaller red-shift in PL spectra compared with that of the CdS shell. The water-soluble CdSe/Cd
x
Zn 1− x
S core–shell QDs were obtained by the encapsulation of amphiphilic poly(styrene-co-maleic anhydride) (PSMA)–ethanolamine (EA) polymers, which was initially dispersed in oil phase. It was found that the CdSe/Cd
x
Zn 1− x
S QDs in water still retained a high PL efficiency as well as a small value in fwhm after encapsulating the CdSe/Cd
x
Zn 1− x
S QDs with PSMA–EA polymers, expanding the applications of these core–shell QDs in aqueous environment.
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JOURNAL OF ALLOYS AND COMPOUNDS
·
2013
·
IF 2.39
Ji-Ming Song,Yu Liu,He-Lin Niu,Chang-Jie Mao,Long-Jiu Cheng,Sheng-Yi Zhang,Yu-Hua Shen
Cu 2 SnSe 3 (copper tin selenide, CTSe) is one of promising copper-based selenides materials in the use of acousto-optic and photovoltaic fields. In this communication, the CTSe nanocrystals was successfully synthesized by a “hot-injection” protocol in the presence of oleylamine (OLA). Selenium powder dissolved in the mixed solution of OLA and dodecanethiol (DT) were injected into a hot solution of OLA, including copper chloride, tin chloride, at a given reaction temperature. The structure, composition and morphology of the synthesized samples were characterized via using powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM) and field-emission scanning electron microscopy (SEM). The results revealed that the as-synthesized nanocrystals were single phase polycrystalline, cubic crystal structure, and high monodispersity with an average diameter of 5 nm. The thermoelectric properties of these dense materials compacted from nanocrystals with the temperature range from 300 K to 598 K were studied. The results exhibit a promising figure-of-merit ZT at 598 K, and it demonstrates that the prepared CTSe could potentially be useful for efficient thermoelectric materials.
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Polymer Chemistry
·
2013
·Vol. 4
·期 14
·4017-4023
·
IF 5.231
Tongbing Sun,Yong Jin,Rui Qi,Shaojun Peng,Baozhu Fan
A novel diselenide-containing mono-cleavable amphiphilic di-block polymer, denoted MPEG-IPDI-SeSe-IPDI-PPG, composed of one hydrophilic poly(ethylene glycol) monomethyl ether (MPEG) block and one hydrophobic polypropylene glycol (PPG) block, was synthesized via four coupling reactions in sequence. MPEG-IPDI-SeSe-IPDI-PPG is able to self-assemble into spherical micelles in aqueous solution. Subsequently, it was found that the spherical micelles have a oxidation-responsiveness and undergo a morphology transformation from spherical micelles to large compound micelles (LCMs) in an oxidative environment (0.5%wt H2O2) due to the unique oxidation-responsive cleavage of the diselenide group, resulting in an initially fast release of loaded Rhodamine B (RB), followed by slow, continuously increasing release. It is anticipated that these mono-cleavable polymer micelles containing diselenide may find application in the field of drug delivery systems.
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MATERIALS RESEARCH INNOVATIONS
·
2013
·
IF 0.321
Y. L. Ding,J. X. Bi,B. Du,X. Y. Hu,F. T. Liu
We have developed an aqueous synthesis for glutathione capped ZnSe nanocrystals. The structure and optical properties of the obtained ZnSe nanocrystals were characterised by X-ray diffraction, dynamic light scattering analysis, TEM, ultraviolet–visible, photoluminescence spectroscopy and Fourier transform infrared spectroscopy. The ZnSe shows a cubic zincblende crystal phase and has a narrow size distribution. Experimental results indicate that the pH value and reaction time play crucial roles in determining optical features. With the pH increasing from 10 to 12, and reaction time from 0 to 2 h, the fluorescence emissions of ZnSe nanocrystals are tuneable between 360 and 405 nm. The high quantum yields are calculated to be in the range of 0·3–22%. Furthermore, the luminescence intensity can be enhanced significantly when the nanocrystal sample is illuminated by room light. The mechanism for the resulting high quality optical properties is also elucidated.
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JOURNAL OF NANOPARTICLE RESEARCH
·
2014
·Vol. 16
·期 8
·1-12
·
IF 2.278
Yang Ping,Chen Hsueh Shin,Zhang Qiang,Shi Ruixia,Wang Junpeng,Che Quande
To investigate the shell deposited kinetics, CdSe quantum dots (QDs) and nanorods (NRs) with a maximum length of 17 nm were fabricated via organic synthesis routes. CdSe with a hexagonal crystal structure (wurtzite) favors epitaxial growth on the {002} surfaces when well-controlled conditions were used. The morphologies and sizes of CdSe samples depended strongly on chemicals and temperature. In the case of 320 °C, CdSe NRs with adjusted length of 7–17 nm were obtained from trioctylphosphine oxide (TOPO) and tetradecylphosphonic acid (TDPA). In contrast, short CdSe NRs (less than 10 nm) were created from octadecylphosphonic acid (ODPA) and trioctylamine (TOA). Spherical CdSe QDs were further fabricated using stearic acid (SA) and TOPO at 300 °C. CdSe cores were coated with Cd 0.5 Zn 0.5 S and CdTe shells. Anisotropic growth occurred during shell deposition because CdS shells grown preferentially on the {001} facet of the CdSe core. In the case of CdSe core prepared from TOPO and TDPA, CdSe/Cd 0.5 Zn 0.5 S core/shell samples prepared from long CdSe NRs (more than 10 nm) revealed a peanut morphology while the core/shell samples created from short ones (less than 10 nm) exhibited a spherical morphology. All of the CdSe/Cd 0.5 Zn 0.5 S core/shell samples revealed a similar length to that of the CdSe cores. This phenomenon was also observed for the core/shell samples fabricated using CdSe NRs prepared by ODPA and TOA. This is ascribed to the well-developed crystal structure of CdSe NRs fabricated using an organic synthesis at high temperature. In contrast, this anisotropic growth did not occur when spherical CdSe QDs prepared from SA and TOPO and the shell (Cd 0.5 Zn 0.5 S) coating carried out using SA and TOA. To indicate the shell depositing process, CdSe NRs fabricated using TDPA and TOPO were coated with a CdTe shell. CdTe monomers were deposited on the middle and tip parts of the CdSe NRs to form a tetrapod-like morphology at 220 °C. This is ascribed to the large difference of structure of CdSe (hexagonal) and CdTe (zinc blende).
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LANGMUIR
·
2014
·
IF 4.384
Yecang Tang,Qian Yang,Ting Wu,Li Liu,Yi Ding,Bo Yu
In this work, a new assembled glucose sensor based on the Ag nanoparticle (AgNP)-enhanced fluorescence of CdSe quantum dots (QDs) was developed. The mercaptoglycerol-modified AgNPs and aminophenylboronic acid-functionalized CdSe QDs are assembled into AgNP-CdSe QD complexes through the formation of a boronate ester bond. As compared to that of bare CdSe QDs, up to a 9-fold fluorescence enhancement and a clear blue shift of the emission peak for AgNP-CdSe QD complexes were observed, which is attributed to the surface plasmon resonance of AgNPs. In addition, the as-formed complexes are gradually disassembled in the presence of glucose molecules because they can replace the AgNPs by competitive binding with boronic acid groups, resulting in the weakening of fluorescence enhancement. The decrease in fluorescence intensity presents a linear relationship with glucose concentration in the range from 2 to 52 mM with a detection limit of 1.86 mM. Such a metal-enhanced QDs fluorescence system may have promising applications in chemical and biological sensors.
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APPLIED CATALYSIS B-ENVIRONMENTAL
·
2014
·
IF 6.007
Peng Wang,Danzhen Li,Jing Chen,Xiaoyun Zhang,Jiangjun Xian,Xue Yang,Xiuzhen Zheng,Xiaofang Li,Yu Shao
In this paper, a facile and green method was employed to synthesize CdSe quantum dots (QDs)-modified TiO 2 . It exhibited much higher photocatalytic activities than both TiO 2 and bulk CdSe-modified TiO 2 on degrading malachite green (MG) aqueous solution under visible light irradiation. The vital role that quantum size effect of CdSe QDs plays in enhancing photocatalytic properties of CdSe QDs-modified TiO 2 is discussed in detail for the first time. Due to the more negative conduction band potentials of CdSe QDs than that of bulk CdSe, the electron transfer rate from CdSe QDs to TiO 2 is much faster than that from bulk CdSe to TiO 2 , which would be beneficial for an efficient charge carrier's separation. As a result, more quantities of active species (O 2 • − , H 2 O 2 , •OH) are generated during the photocataltytic reaction in CdSe QDs-modified TiO 2 system. This work could not only provide a facile and green strategy to fabricate semiconductor QDs-modified TiO 2 photocatalyst but also contribute to a deeper understanding of the specific role of semiconductor QDs during the photocatalytic reaction process.
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Nanoscale Research Letters
·
2014
·Vol. 9
·期 1
·1-13
·
IF 2.481
Li Chao,Ji Yang,Wang Can,Liang Shujing,Pan Fei,Zhang Chunlei,Chen Feng,Fu Hualin,Wang Kan,Cui Daxiang
Successful development of safe and highly effective nanoprobes for targeted imaging of in vivo early gastric cancer is a great challenge. Herein, we choose the CdSe/ZnS (core-shell) quantum dots (QDs) as prototypical materials, synthesized one kind of a new amphiphilic polymer including dentate-like alkyl chains and multiple carboxyl groups, and then used the prepared amphiphilic polymer to modify QDs. The resultant amphiphilic polymer engineered QDs (PQDs) were conjugated with BRCAA1 and Her2 monoclonal antibody, and prepared BRCAA1 antibody- and Her2 antibody-conjugated QDs were used for in vitro MGC803 cell labeling and in vivo targeted imaging of gastric cancer cells. Results showed that the PQDs exhibited good water solubility, strong photoluminescence (PL) intensity, and good biocompatibility. BRCAA1 antibody- and Her2 antibody-conjugated QD nanoprobes successfully realized targeted imaging of in vivo gastric cancer MGC803 cells. In conclusion, BRCAA1 antibody- and Her2 antibody-conjugated PQDs have great potential in applications such as single cell labeling and in vivo tracking, and targeted imaging and therapeutic effects' evaluation of in vivo early gastric cancer cells in the near future.
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GREEN CHEMISTRY
·
2014
·Vol. 17
·期 2
·1269-1275
·
IF 6.852
Qingwen Tian,Lijian Huang,Wangen Zhao,Yanchun Yang,Gang Wang,Daocheng Pan
Aqueous solution deposition of metal chalcogenide semiconductor thin films is considered a green and low-cost approach. However, it is hard to find a general aqueous solution approach to deposit various kinds of high-quality metal sulfide thin films. Here, we describe a green and robust ammonium thioglycolate aqueous solution approach, and fifteen types of metal sulfide precursor solutions (metal = Cu, Zn, Sn, Ge, In, Sb, Mg, Cd, Mn, Bi, Fe, Ni, Li, Na, K) can be prepared using metal oxides or metal hydroxides as raw materials at room temperature under an air atmosphere. Moreover, elemental sulfur and selenium can also be highly dissolved. By this green route, high quality CZTS nanocrystal thin films can be deposited by directly coating the mixed Cu, Zn, and Sn precursor solutions without the need for complex nanocrystal synthesis. The remarkable power conversion efficiency of 6.62% was achieved, which is the highest value for aqueous solution deposited CZTSSe thin film solar cells.
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BIOSENSORS & BIOELECTRONICS
·
2015
·
IF 6.409
Ke-Jing Huang,Hong-Lei Shuai,Ji-Zong Zhang
A highly sensitive and ultrasensitive electrochemical aptasensor for platelet-derived growth factor BB (PDGF-BB) detection is fabricated based on layered molybdenum selenide–graphene (MoSe 2 –Gr) composites and Exonuclease III (Exo III)-aided signal amplification . MoSe 2 –Gr is prepared by a simple hydrothermal method and used as a promising sensing platform. Exo III has a specifical exo-deoxyribonuclease activity for duplex DNAs in the direction from 3′ to 5′ terminus, however its activity is limited on the duplex DNAs with more than 4 mismatched terminal bases at 3′ ends. Herein, aptamer and complementary DNA (cDNA) sequences are designed with four thymine bases on 3′ ends. In the presence of target protein, the aptamer associates with it and facilitates the formation of duplex DNA between cDNA and signal DNA. The duplex DNA then is digested by Exo III and releases cDNA, which hybridizes with signal DNA to perform a new cleavage process. Nevertheless, in the absence of target protein, the aptamer hybridizes with cDNA will inhibit the Exo III-assisted nucleotides cleavage. The signal DNA then hybridizes with capture DNA on the electrode. Subsequently, horse radish peroxidase is fixed on electrode by avidin–biotin reaction and then catalyzes hydrogen peroxide and hydroquinone to produce electrochemical response. Therefore, a bridge can be established between the concentration of target protein and the degree of the attenuation of the obtained signal, providing a quantitative measure of target protein with a broad detection range of 0.0001–1 nM and a detection limit of 20 fM.
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SENSORS AND ACTUATORS B-CHEMICAL
·
2015
·
IF 4.097
Ke-Jing Huang,Hong-Lei Shuai,Ying-Xu Chen
Sensitive detection of ochratoxin A (OTA) plays an important role in the field of food safety control. In this study, we are reporting for the first time an electrochemical biosensor which employs the integration of MoSe 2 nanoflowers , Au nanoparticles (AuNPs), aptamer and the guanine-rich complementary DNA sequence for the sensitive detection of OTA. MoSe 2 nanoflowers are prepared by a simple hydrothermal method and used as a promising sensing platform based on its large surface area. The methylene blue is used as a tracer and a guanine-rich complementary DNA sequence is designed to bind with the unbound OTA aptamer for signal amplification . The aptamer is immobilized on the AuNPs/MoSe 2 modified electrode surface through Au–S interaction. Since OTA can competitively bind with the aptamer due to their high affinity, the presence of OTA will induce the decrease of guanine-rich DNA on the electrode surface , in turn reduces the signal of methylene blue which can specifically adsorb to the guanine units of DNA. The proposed assay shows a good linear relationship within the range of 0.0001–1 nM with a detection limit of 0.08 pM for OTA. The developed biosensor has been applied to determine OTA concentration in wine samples.
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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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