Artykuły w czasopismach: „CdTe NCs”

1

Kadim, Akeel M. "White Light Generation from Emissive Hybrid Nanocrystals CdSe/CdTe/CdS Core/Shell/Shell System". Nano Hybrids and Composites 27 (listopad 2019): 1–10. http://dx.doi.org/10.4028/www.scientific.net/nhc.27.1.

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New nanocrystals (NCs) were engineered with a core/shell/shell system consisting of CdSe core/ CdTe shell/ CdS shell. The white light generation mechanism was described depending on mixing colors from the illuminated CdSe/CdTe/CdS core/shell/shell nanocrystals. The color mixed in CdSe/CdTe/CdS core/shell/shell NCs system were used to generate extreme white light when illuminated by InGaN/GaN UV LED (λ=360 nm) the core/shell/shell NCs system tuned the chromaticity coordinates to (0.332, 0.340) and increased the intensity of the emitted white light. The synthesis of the CdSe/CdTe/CdS core/shell/shell NCs were confirmed by SEM, AFM, XRD and photoluminescence (PL) experiments due to create of surface states defects information. This enhancement was recognized to the overlap of emission with the photoluminescence (PL) spectrum of CdSe/CdTe/CdS core/shell/shell NCs which indications to a cold white light generation. Current-voltage (I–V) characteristics indicate that the output current is good compared to the few voltages (6 V) used which give acceptable results to get a generation of white light.

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Hou, Mingyue, Zhaohua Zhou, Ao Xu, Kening Xiao, Jiakun Li, Donghuan Qin, Wei Xu i Lintao Hou. "Synthesis of Group II-VI Semiconductor Nanocrystals via Phosphine Free Method and Their Application in Solution Processed Photovoltaic Devices". Nanomaterials 11, nr 8 (15.08.2021): 2071. http://dx.doi.org/10.3390/nano11082071.

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Solution-processed CdTe semiconductor nanocrystals (NCs) have exhibited astonishing potential in fabricating low-cost, low materials consumption and highly efficient photovoltaic devices. However, most of the conventional CdTe NCs reported are synthesized through high temperature microemulsion method with high toxic trioctylphosphine tellurite (TOP-Te) or tributylphosphine tellurite (TBP-Te) as tellurium precursor. These hazardous substances used in the fabrication process of CdTe NCs are drawing them back from further application. Herein, we report a phosphine-free method for synthesizing group II-VI semiconductor NCs with alkyl amine and alkyl acid as ligands. Based on various characterizations like UV-vis absorption (UV), transmission electron microscope (TEM), and X-ray diffraction (XRD), among others, the properties of the as-synthesized CdS, CdSe, and CdTe NCs are determined. High-quality semiconductor NCs with easily controlled size and morphology could be fabricated through this phosphine-free method. To further investigate its potential to industrial application, NCs solar cells with device configuration of ITO/ZnO/CdSe/CdTe/Au and ITO/ZnO/CdS/CdTe/Au are fabricated based on NCs synthesized by this method. By optimizing the device fabrication conditions, the champion device exhibited power conversion efficiency (PCE) of 2.28%. This research paves the way for industrial production of low-cost and environmentally friendly NCs photovoltaic devices.

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Xie, Ya, Qiongxuan Tan, Zhitao Zhang, Kuankuan Lu, Miaozi Li, Wei Xu, Donghuan Qin, Yangdong Zhang, Lintao Hou i Hongbin Wu. "Improving performance in CdTe/CdSe nanocrystals solar cells by using bulk nano-heterojunctions". Journal of Materials Chemistry C 4, nr 27 (2016): 6483–91. http://dx.doi.org/10.1039/c6tc01571a.

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Dzhagan, Volodymyr, Nazar Mazur, Olga Kapush, Oleksandr Selyshchev, Anatolii Karnaukhov, Oleg A. Yeshchenko, Mykola I. Danylenko, Volodymyr Yukhymchuk i Dietrich R. T. Zahn. "Core and Shell Contributions to the Phonon Spectra of CdTe/CdS Quantum Dots". Nanomaterials 13, nr 5 (1.03.2023): 921. http://dx.doi.org/10.3390/nano13050921.

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The parameters of the shell and interface in semiconductor core/shell nanocrystals (NCs) are determinant for their optical properties and charge transfer but are challenging to be studied. Raman spectroscopy was shown earlier to be a suitable informative probe of the core/shell structure. Here, we report the results of a spectroscopic study of CdTe NCs synthesized by a facile route in water, using thioglycolic acid (TGA) as a stabilizer. Both core-level X-ray photoelectron (XPS) and vibrational (Raman and infrared) spectra show that using thiol during the synthesis results in the formation of a CdS shell around the CdTe core NCs. Even though the spectral positions of the optical absorption and photoluminescence bands of such NCs are determined by the CdTe core, the far-infrared absorption and resonant Raman scattering spectra are dominated by the vibrations related with the shell. The physical mechanism of the observed effect is discussed and opposed to the results reported before for thiol-free CdTe Ns as well as CdSe/CdS and CdSe/ZnS core/shell NC systems, where the core phonons were clearly detected under similar experimental conditions.

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SHEN, QI-HUI, YAN LIU, XI YU, XIAO-YANG LIU, MING-QIANG ZOU, JIN-FENG LI i JIAN-GUANG ZHOU. "FORMATION OF II–VI SEMICONDUCTOR NANOCRYSTALS WITH TUNABLE VISIBLE EMISSION IN AQUEOUS SOLUTION PROMOTED BY HYDRAZINE". Nano 07, nr 06 (grudzień 2012): 1250046. http://dx.doi.org/10.1142/s1793292012500464.

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II–VI Semiconductor nanocrystals (NCs) with tunable visible emission, such as CdS , CdSe and CdTe , were synthesized in aqueous solution using thiols as capping molecules. Hydrazine was found to promote the growth of NCs through a special mechanism. In only a few hours, the synthesis process was completed at room temperature. Under moderate conditions, the capping molecules not only changed the growth rate of NCs simply by varying the concentration, but also altered the spectral properties of NCs. The capping molecules with amino groups were propitious to the growth of CdS NCs, whereas the kinetic growth of CdS NCs was more affected by the surface passivation efficiency of NCs than by steric hindrance in the system. The fastest growth of the CdS NCs was achieved when glutathione was used as a capping molecule, while the emission of CdS and CdSe NCs were shown to remain steady and tunable using the same capping molecule. The growth rate of 3-mercaptopropionic acid-capped CdS and CdSe NCs slowed down significantly, while CdTe NCs were obtained with excellent emission properties when capped with the same molecule. Furthermore, our approach will also be useful for the study of the kinetic growth of NCs in aqueous solution.

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Liu, Ning, Zhi Min Yuan, Jie Yang, Yu Lan Zhang, Rui Li Zhang, Yong Qiang Cao, Ai Yu Zhang, Yuan Na Zhu i Ping Yang. "Preparation and Photoluminescence of Hybrid SiO₂-Coated CdTe Nanocrystals". Advanced Materials Research 306-307 (sierpień 2011): 1194–97. http://dx.doi.org/10.4028/www.scientific.net/amr.306-307.1194.

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Novel hybrid SiO2-coated CdTe core-shell nanocrystals (NCs) were fabricated by re-dispersing green-emitting CdTe NCs in a solution of Cd2+ions, thioglycolic acid (TGA), tetraethyl orthosilicate and ammonia with a sol-gel reaction at room temperature and a further reflux procedure. The hybrid NCs consisted of a CdTe core and a hybrid SiO2shell with CdS-like clusters. The clusters created by the reaction of Cd2+and S2-generated by the decomposition of TGA during reflux. The hybrid NCs exhibited tunable photoluminescence (PL) color from green to red and high PL quantum yield (PLQY). The CdS-like clusters play an important role for the hybrid NCs with numerous PL properties. Compared with initial CdTe NCs, the PLQY of the hybrid NCs increased from 18% to 47% together with a red-shifted PL peak wavelength of 61 nm. The average lifetime of the hybrid NCs (39 ns) is longer than that of initial CdTe NCs (25 ns). The high PLQY and the hybrid shell make CdTe NCs an important application for biological technique.

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Wang, Chao, Qiang Ma i Xingguang Su. "Synthesis of CdTe Nanocrystals with Mercaptosuccinic Acid as Stabilizer". Journal of Nanoscience and Nanotechnology 8, nr 9 (1.09.2008): 4408–14. http://dx.doi.org/10.1166/jnn.2008.269.

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Water soluble high quality CdTe nanocrystals (NCs) with mercaptosuccinic acid (MSA) as stabilizer are prepared by refluxing and hydrothermal synthesis in this paper. The MSA stabilizer which comprises both thioglycolic acid (TGA)-like and 3-mercaptopropionic acid (MPA)-like moieties can accelerate the whole growth process of CdTe NCs comparing with TGA-like or MPA-like stabilizer. It takes only 5 min and 2 hours to obtain green emitting (luminescence maximum at 526 nm) and red emitting (luminescence maximum at ∼650 nm) from CdTe NCs, respectively. In this study, the influences of the ratios of precursors and temperature on CdTe NCs synthesis were studied in detail, and the stable CdTe NCs with high photoluminescence quantum yield and narrow size distribution can be obtained under optimal condition by both routes. The luminescence quantum yield of the green-yellow emitting CdTe NCs obtained in this study can reach 75.2%.

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Wang, Mei Ping, Jin Hui Lin i Xiao Li Hao. "Preparation and Characterization of CdTe/SiO₂ Composite". Advanced Materials Research 233-235 (maj 2011): 1946–49. http://dx.doi.org/10.4028/www.scientific.net/amr.233-235.1946.

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TGA- stabilized CdTe nanocrystals (NCs) were prepared using sodium tellurite as tellurium source, which avoids the cumbersome processes associated with H2Te or NaHTe sources. Fluorescent CdTe/SiO2composites were prepared by a sol–gel method without the exchange of surface ligands. The composites were characterized with TEM and fluorescence spectrophotometer and investigated their stability in phosphate-buffered saline (PBS) buffer. CdTe NCs were loaded into the core of silica spheres during the formation of composite spheres. In contrast to CdTe NCs in aqueous solutions, CdTe NCs in the composite revealed better stability and the luminescence peak show red-shift.

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Xu, Jia, Yatao Pan, Zhongran Wei, Shida Luo, Xia Ran, Yulu He, Renming Liu, Zhen Chi i Lijun Guo. "Efficient charge separation and enhanced photocurrent of CdTe quantum dots-Au nanoclusters composite with type-II band alignment". Applied Physics Letters 120, nr 14 (4.04.2022): 143902. http://dx.doi.org/10.1063/5.0083889.

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Quantum dots (QDs)-based composites are promising candidates for optoelectronic and photonic devices. Understanding the photo-induced carrier dynamics is fundamental and crucial for improving the photoelectric conversion efficiency of nanocomposites. In this work, we have constructed nanocomposite hybridizing CdTe QDs with Au nanoclusters (Au NCs) and investigated the ultrafast carrier dynamics and enhanced photoelectric properties. The concurrent photoluminescence quenching and lifetime decreasing of CdTe QDs and Au NCs suggest a type-II band alignment, facilitating the carrier dynamics in the CdTe QDs-Au NCs' nanocomposite. The transient absorption measurements demonstrate an ultrafast and efficient electron transfer from CdTe QDs to Au NCs, effectively promoting the charge separation and inhibiting the exciton recombination. We found that the quantum efficiency of hot electron transfer can reach ∼50% with a rate constant of 1.01 × 1013 s−1 for the CdTe QDs-Au NCs' nanocomposite. As a result, the photocurrent performance of the CdTe QDs-Au NC device has been dramatically enhanced due to the efficient separation of photogenerated carriers, compared to that of individual CdTe QDs and Au NCs. These findings are significant for developing the light-harvesting and photoelectric devices based on semiconductor QDs and metal NCs.

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Slyusarenko, Nina, Marina Gerasimova, Alexei Plotnikov, Nikolai Gaponik i Evgenia Slyusareva. "Photoluminescence properties of self-assembled chitosan-based composites containing semiconductor nanocrystals". Physical Chemistry Chemical Physics 21, nr 9 (2019): 4831–38. http://dx.doi.org/10.1039/c8cp07051b.

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The photoluminescence (PL) properties of composites obtained by embedding green-emitting semiconductor nanocrystals (NCs) of two different types (thiol-capped CdTe and CdSe/ZnS) into chitosan-based biopolymer particles were investigated.

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Yang, Rui, Yuxi Yan, Ying Mu, Wei Ji, Xuwen Li, MingQiang Zou, Qiang Fei i Qinhan Jin. "A Rapid and Facile Method for Hydrothermal Synthesis of CdTe Nanocrystals Under Mild Conditions". Journal of Nanoscience and Nanotechnology 6, nr 1 (1.01.2006): 215–20. http://dx.doi.org/10.1166/jnn.2006.17933.

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By using a novel procedure, a new kind of water-soluble CdTe nanocrystals (NCs) is synthesized in aqueous solutions at the temperature of 100 °C. In this procedure, tripeptide thiol glutathione was used as stabilizing agent, CdTe NCs with controllable photoluminescence wavelength from 500 nm to 680 nm were prepared within two hours. Compared with CdTe NCs prepared with thiohydracrylic acid as stabilizing agent, as-prepared NCs show much narrower photoluminescence FWHM, more symmetrical emission peak and higher photoluminescence quantum yield. The surface structure of as-prepared CdTe NCs is deduced, therefore, there may be some unreported circular structure on the surface. Experimental results show that as-prepared NCs have very good biological compatibility and they are nontoxic. And these CdTe NCs can conjugate with biological molecules for further biological luminescence study. The proposed hydrothermal synthesis procedure has the advantage of simplicity, inexpensiveness, time saving and mild operating conditions.

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Mittal, Mona, Saurabh Gautam, Pramit Kumar Chowdhury, Shashank Deep i Sameer Sapra. "Role of Tryptophan in Protein–Nanocrystals Interaction: Energy or Charge Transfer". Zeitschrift für Physikalische Chemie 233, nr 1 (19.12.2018): 41–54. http://dx.doi.org/10.1515/zpch-2017-1088.

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Abstract The understanding of the interaction between the semiconductor nanocrystals (NCs) and the proteins are essential for design and fabrication of nanocomposites for application in the field of biotechnology. Herein, we have studied the interaction between CdTe NCs and the proteins by steady-state and time-resolved photoluminescence (PL) spectroscopy. The steady-state PL intensity of CdTe NCs is quenched and enhanced in the presence of lysozyme and bovine serum albumin, respectively. However, the PL intensity of CdTe NCs is not affected with α-synuclein, indicating the role of tryptophan moiety in the protein–NCs interaction. The detailed analysis of PL data allows us to elucidate the dominant mechanism of interaction, i.e. charge or energy transfer, depending on the location of tryptophan residues in the protein. Assuming a Poisson statistic of lysozymes around NCs, the Poisson binding model is used to understand the kinetics of charge transfer from CdTe NCs to the lysozyme. It provides the average number of lysozymes present on the surface of one CdTe NC.

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Xu, Ao, Qichuan Huang, Kaiying Luo, Donghuan Qin, Wei Xu, Dan Wang i Lintao Hou. "Efficient Nanocrystal Photovoltaics with PTAA as Hole Transport Layer". Nanomaterials 12, nr 17 (3.09.2022): 3067. http://dx.doi.org/10.3390/nano12173067.

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The power conversion efficiency (PCE) of solution-processed CdTe nanocrystals (NCs) solar cells has been significantly promoted in recent years due to the optimization of device design by advanced interface engineering techniques. However, further development of CdTe NC solar cells is still limited by the low open-circuit voltage (Voc) (mostly in range of 0.5–0.7 V), which is mainly attributed to the charge recombination at the CdTe/electrode interface. Herein, we demonstrate a high-efficiency CdTe NCs solar cell by using organic polymer poly[bis(4–phenyl)(2,4,6–trimethylphenyl)amine] (PTAA) as the hole transport layer (HTL) to decrease the interface recombination and enhance the Voc. The solar cell with the architecture of ITO/ZnO/CdS/CdSe/CdTe/PTAA/Au was fabricated via a layer-by-layer solution process. Experimental results show that PTAA offers better back contact for reducing interface resistance than the device without HTL. It is found that a dipole layer is produced between the CdTe NC thin film and the back contact electrode; thus the built–in electric field (Vbi) is reinforced, allowing more efficient carrier separation. By introducing the PTAA HTL in the device, the open–circuit voltage, short-circuit current density and the fill factor are simultaneously improved, leading to a high PCE of 6.95%, which is increased by 30% compared to that of the control device without HTL (5.3%). This work suggests that the widely used PTAA is preferred as the excellent HTL for achieving highly efficient CdTe NC solar cells.

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Budzulyak, S. I., V. M. Yermakov, O. A. Kapush, D. V. Korbutyak, V. М. Tomashyk, Z. F. Tomashyk, L. I. Trishchuk, S. D. Boruk i L. A. Demchyna. "Photoluminescent Properties of CdTe Nanocrystals in Colloidal Solutions and Polymer Films". Фізика і хімія твердого тіла 17, nr 1 (15.03.2016): 60–64. http://dx.doi.org/10.15330/pcss.17.1.60-64.

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Using stabilizers and promoters we have obtained colloidal CdTe nanocrystals (NCs) in aqueous solutions. Incorporation of the CdTe NCs into polymer films has been fulfilled subsequently. It is shown that the use of vinyl acetate-acrylate copolymer as the matrix material for CdTe NC incorporation from colloidal solutions allows to get stable and nontoxic nanoheterogeneous film structures, which are characterized by satisfactory values of the photoluminescence quantum yield. Photoluminescence characteristics of the studied materials have been analyzed.

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Bastola, Ebin, Kamala Khanal Subedi, Khagendra P. Bhandari i Randy J. Ellingson. "Solution-processed Nanocrystal Based Thin Films as Hole Transport Materials in Cadmium Telluride Photovoltaics". MRS Advances 3, nr 41 (2018): 2441–47. http://dx.doi.org/10.1557/adv.2018.349.

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ABSTRACTThe cadmium telluride (CdTe) photovoltaic (PV) comprise an efficient and cost-effective technology for harvesting solar energy. However, device efficiency remains limited in part by low-open circuit voltage (VOC) and fill factor (FF) due to inefficient transport of photo-generated charge carriers. Given the deep valence band of CdTe, the use of copper/gold (Cu/Au) as a back contact serves primarily to narrow the width of the inherent Schottky junction evident in CdTe solar cells (in our laboratory, Cu/Au has been used as a standard back contact). For efficient transport of carriers to and into the back contact, a hole transport layer (HTL) is desired with valence band edge comparable to that of CdTe (∼ -5.9 eV). Here, we report solution-processed nanocrystal (NCs) based thin films as HTLs in CdTe solar cells. The earth abundant materials we discuss include iron pyrite (FeS2), nickel-alloyed iron pyrite (NixFe1-xS2), zinc copper sulfide (ZnxCu1-xS) nanocomposites, and perovskite-based films. The FeS2 and NixFe1-xS2 NCs are synthesized by a hot-injection route, and thin films are fabricated by drop-casting, and spin-coating techniques using colloidal NCs. ZnxCu1-xS thin films are fabricated by chemical bath deposition. These NC-based thin films are applied and studied as the HTLs in CdTe devices. On using these materials, the device performance can be increased up to 10% compared to the standard Cu/Au back contact. Here, we discuss the benefits, challenges, and opportunities for these back contact materials in CdTe photovoltaics.

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Chang, Qing, Jingrong Sui, Zhijun Chai i Wenzhi Wu. "Temperature-Dependent Excitonic Photoluminescence and Nonlinear Absorption of CdTe Nanocrystal/Polyvinyl Alcohol Films". Nanomaterials 11, nr 7 (6.07.2021): 1761. http://dx.doi.org/10.3390/nano11071761.

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The temperature dependence of the excitonic photoluminescence (PL) and nonlinear absorption characteristics of CdTe nanocrystals (NCs)/polyvinyl alcohol (PVA) film are investigated using steady-state/time-resolved PL spectroscopy and Z-scan methods. The excitonic PL peaks of CdTe NCs can be observed at the wavelengths from 560 to 670 nm, with size changes from 2.1 to 3.9 nm. From the temperature-dependent PL spectra, the smaller photon energy of the PL emission peak, the rapidly decreasing PL intensity, and the wider linewidth are observed with increasing temperature from 80 to 300 K. It is revealed that the excitonic PL is composed of both trapped state and band-edge excitonic state, which presents biexponential fitting dynamics. The short-lived species is due to the surface-trapped state recombination in NCs, which has a photogenerated trapped channel and a time-resolved peak shift. The species with a long-lived lifetime is ascribed to the intrinsic excitonic recombination. Through the femtosecond Z-scan method, the nonlinear absorption coefficient becomes smaller with the increase in the size of the NCs. The optical properties of the CdTe NC/PVA film show the potential of II-VI traditional NCs as display and luminescent materials that can utilize the combination of excitonic PL and nonlinear absorption for expanded functionality.

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Yang, Ping, Hongsheng Sun, Aiyu Zhang, Yongqiang Cao, Qinghui Jiang, Ruixia Shi, Futian Liu i Guangjun Zhou. "Luminescent evolution of hybrid SiO2-coated CdTe NCs". Colloids and Surfaces A: Physicochemical and Engineering Aspects 377, nr 1-3 (marzec 2011): 336–41. http://dx.doi.org/10.1016/j.colsurfa.2011.01.008.

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Zhao, Zhihui, Cunzhen Geng, Xihui Zhao, Zhixin Xue, Fengyu Quan i Yanzhi Xia. "Preparation of CdTe/Alginate Textile Fibres with Controllable Fluorescence Emission through a Wet-Spinning Process and Application in the Trace Detection of Hg2+ Ions". Nanomaterials 9, nr 4 (8.04.2019): 570. http://dx.doi.org/10.3390/nano9040570.

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Fluorescent textile fibres (FTFs) are widely used in many industrial fields. However, in addition to fibres with good fluorescence, fibres with excellent colour controllability, structural stability and appropriate mechanical strength still need to be developed. In this work, CdTe/alginate composite FTFs are prepared by taking advantage of the interactions between CdTe nanocrystals (NCs) and alginate macromolecules via a wet-spinning machine with a CaCl2 aqueous solution as the coagulation bath. CdTe NCs were chemically fixed in the fibre due to the interactions among surface ligands, macromolecules and coagulators (calcium ions), which ensured the excellent dispersity and good stability of the fibres. Förster resonance energy transfer (FRET) between NCs in the fibre was found to be restricted, which means that the emission colour of the fibres was totally controllable and could be predicted. Other properties of alginate fibres, such as flame retardance and mechanical strength, were also well preserved in the fluorescent fibres. Finally, FTFs showed good selectivity toward trace Hg2+ ions over other metallic ions, and the detection could be identified by the naked eye.

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Dzhagan, Volodymyr, Oleksandr Stroyuk, Oleksandra Raievska, Oksana Isaieva, Olga Kapush, Oleksandr Selyshchev, Volodymyr Yukhymchuk, Mykhailo Valakh i Dietrich R. T. Zahn. "Photoinduced Enhancement of Photoluminescence of Colloidal II-VI Nanocrystals in Polymer Matrices". Nanomaterials 10, nr 12 (21.12.2020): 2565. http://dx.doi.org/10.3390/nano10122565.

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The environment strongly affects both the fundamental physical properties of semiconductor nanocrystals (NCs) and their functionality. Embedding NCs in polymer matrices is an efficient way to create a desirable NC environment needed for tailoring the NC properties and protecting NCs from adverse environmental factors. Luminescent NCs in optically transparent polymers have been investigated due to their perspective applications in photonics and bio-imaging. Here, we report on the manifestations of photo-induced enhancement of photoluminescence (PL) of aqueous colloidal NCs embedded in water-soluble polymers. Based on the comparison of results obtained on bare and core/shell NCs, NCs of different compounds (CdSe, CdTe, ZnO) as well as different embedding polymers, we conclude on the most probable mechanism of the photoenhancement for these sorts of systems. Contrary to photoenhancement observed earlier as a result of surface photocorrosion, we do not observe any change in peak position and width of the excitonic PL. Therefore, we suggest that the saturation of trap states by accumulated photo-excited charges plays a key role in the observed enhancement of the radiative recombination. This suggestion is supported by the unique temperature dependence of the trap PL band as well as by power-dependent PL measurement.

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Sun, Haizhu, Junhu Zhang, Ye Tian, Yang Ning, Hao Zhang, Jie Ju, Delong Li, Shidong Xiang i Bai Yang. "Multifunctional Composites Obtained by Incorporating Nanocrystals into Decorated PVK Polymers". Journal of Nanomaterials 2007 (2007): 1–7. http://dx.doi.org/10.1155/2007/38589.

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Poly(vinylcarbazole) (PVK) was decorated with surfactant group to achieve amphiphilic polymer with luminescent property. The composition and properties of the polymers were systematically investigated using FTIR, EA, TGA, UV-Vis, and PL characterizations. Different CdTe nanocrystals (NCs) prepared in aqueous medium were directly transferred to organic phase using the PVK-based polymers. The quantum yield of NCs in the composites had been improved by 50% compared with their parent aqueous solution due to the short distance from carbazole moieties to NCs, which facilitated the Förster resonant energy transfer (FRET) between them. Moreover, efficient electron transfer at the interface of NCs and polymers had been confirmed which also indicated the application in photovoltaic cell for such composites.

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Frolova, Elena, Tobias Otto, Nikolai Gaponik i Vladimir Lesnyak. "Incorporation of CdTe Nanocrystals into Metal Oxide Matrices Towards Inorganic Nanocomposite Materials". Zeitschrift für Physikalische Chemie 232, nr 9-11 (28.08.2018): 1335–52. http://dx.doi.org/10.1515/zpch-2018-1139.

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Abstract In this work we present a technique of incorporation of semiconductor CdTe nanocrystals (NCs) into metal oxide matrices prepared by inorganic sol-gel method. As the matrices, we chose alumina and aluminum tin oxide, which are optically transparent in the visible region. Among them the first is electrically insulating, while the second is conductive and thus can be used in optoelectronic devices. We found optimal synthetic parameters allowing us to maintain optical properties of the NCs in both matrices even after heating up to 150°C in air. Therefore, in our approach we overcame a common problem of degradation of the optical properties of semiconductor NCs in oxide matrices as a result of the incorporation and subsequent interaction with the matrix. The resulting materials were characterized in detail from the point of view of their optical and structural properties. Based on the results obtained, we suggest the formation mechanism of these materials. Semiconductor NCs embedded in robust and optically transparent metal oxides offer promising applications in optical switching, optical filtering, waveguides, light emitting diodes, and solar concentrators.

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MOLAEI, M., i S. POURJAFARI. "Investigation of electroluminescence properties of CdTe@CdS core-shell nanocrystals (NCs)". Bulletin of Materials Science 37, nr 1 (luty 2014): 9–13. http://dx.doi.org/10.1007/s12034-014-0625-x.

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POURJAFARI, S., E. SAIEVARE-IRANIZAD i M. MOLAEI. "INVESTIGATION OF LIGANDS AND TEMPRATURE EFFECTS ON THE SIZE OF AQUEOUS PHASE SYNTHESIZED CDTE NANOCRYSTALS". International Journal of Modern Physics: Conference Series 05 (styczeń 2012): 242–50. http://dx.doi.org/10.1142/s2010194512002085.

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The synthesis and properties of high luminescent thio-stabilized nanocrystals (NCs) in aqueous media was discussed in this paper. The sharp peaks of photoluminescence ( PL ) and full width at half-maximum (fwhm), were observed in the range of 50 to 70nm. The PH was 9 and the molar ratio of Cd to thiol (1:2.4) was constant during the experiment. The stabilized NCs through thioglycolic acid ( TGA ) show great luminosity in which the spectral of PL emission is variable with controlling the size of NCs. The size ranges of thioglycerol( TG ) stabilized NCs and the spectral range of PL emission are more limited than TGA in the same condition. The concentration of thio-ligands and heating time are two factors that that will discuss in this paper to control the size of NCs.

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Kapush, O. A., S. I. Budzulyak, D. V. Korbutyak, K. S. Dremlyuzhenko, B. N. Kulchitsky, О. G. Kosinov i A. I. Yemets. "Photoluminescence Properties of Nanoheterogenic Film Structures of NCs CdTe/TGA/Vinyl Acetate-Acrylate Copolymer". Journal of Nano- and Electronic Physics 10, nr 4 (2018): 04009–1. http://dx.doi.org/10.21272/jnep.10(4).04009.

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Mei, Xianglin, Bin Wu, Xiuzhen Guo, Xiaolin Liu, Zhitao Rong, Songwei Liu, Yanru Chen i in. "Efficient CdTe Nanocrystal/TiO2 Hetero-Junction Solar Cells with Open Circuit Voltage Breaking 0.8 V by Incorporating A Thin Layer of CdS Nanocrystal". Nanomaterials 8, nr 8 (13.08.2018): 614. http://dx.doi.org/10.3390/nano8080614.

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Nanocrystal solar cells (NCs) allow for large scale solution processing under ambient conditions, permitting a promising approach for low-cost photovoltaic products. Although an up to 10% power conversion efficiency (PCE) has been realized with the development of device fabrication technologies, the open circuit voltage (Voc) of CdTe NC solar cells has stagnated below 0.7 V, which is significantly lower than most CdTe thin film solar cells fabricated by vacuum technology (around 0.8 V~0.9 V). To further improve the NC solar cells’ performance, an enhancement in the Voc towards 0.8–1.0 V is urgently required. Given the unique processing technologies and physical properties in CdTe NC, the design of an optimized band alignment and improved junction quality are important issues to obtain efficient solar cells coupled with high Voc. In this work, an efficient method was developed to improve the performance and Voc of solution-processed CdTe nanocrystal/TiO2 hetero-junction solar cells. A thin layer of solution-processed CdS NC film (~5 nm) as introduced into CdTe NC/TiO2 to construct hetero-junction solar cells with an optimized band alignment and p-n junction quality, which resulted in a low dark current density and reduced carrier recombination. As a result, devices with improved performance (5.16% compared to 2.63% for the control device) and a Voc as high as 0.83 V were obtained; this Voc value is a record for a solution-processed CdTe NC solar cell.

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Kapush, О. A., I. O. Mazarchuk, L. І. Trіshchuk, V. Y. Morozovska, S. D. Boruk, S. I. Budzulyak, D. V. Korbutyak, B. N. Kulchitsky, O. G. Kosinov i R. G. Abaszade. "Influence of the nature of the dispersion medium on the optical properties of CdTe nanocrystals during sedimentation deposition". Chernivtsi University Scientific Herald. Chemistry, nr 819 (2019): 7–11. http://dx.doi.org/10.31861/chem-2019-819-01.

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The physicochemical properties of low-dimensional structures based on CdTe obtained are investigated by the method of colloidal synthesis. The analysis of the optical absorption spectra and the luminescence intensity of the CdTe colloidal NCs showed that the nature of the dispersion medium significantly affects their optical properties. The optical absorption spectra of the CdTe NK fractions obtained by dissolving the flocs in deionized water and in deionized water with the addition of NaOH have been shown to have the same character. However, the addition of NaOH results in a shift of the absorption maximum by 8-12 nm into the longwave region. This suggested that the addition of NaOH to the colloidal solution of NK CdTe during sedimentation deposition leads to the aggregation of cadmium telluride particles. The addition of NaOH results in the quenching of photoluminescence. It can be assumed that during the sedimentation deposition there is a leaching of THC to a critical concentration, therefore, due to insufficient stabilization of the surface of the NC CdTe, a rapid aggregation of particles occurs and a loss of sedimentation stability of the solution is observed, which causes the PL quenching. The analysis of the optical absorption and photoluminescence spectra of the fractions of the colloidal solution of NC CdTe obtained by using DMF as a dispersion medium during the sedimentation deposition leads to the conclusion that the nature of the dispersion medium significantly affects the optical properties of CdTe NC. The maxima of the OP spectra corresponding to the first exciton transition of all fractions are shifted to the longwave region and change their shape compared to the corresponding spectra for the aqueous fractions. In this case, the PL intensity of the first and second fractions of CdTe NC in DMF is approximately 100 ppm. exceeds the PL intensity of the aqueous fractions, which can be explained by the fact that DMF, unlike deionized water, does not wash out THC from the surface of the CdTe NC.

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Chai, Jiye, Xinru Yu, Jian Zhao, Aili Sun, Xizhi Shi i Dexiang Li. "An Electrochemiluminescence Sensor Based on Nafion/Magnetic Fe3O4 Nanocrystals Modified Electrode for the Determination of Bisphenol A in Environmental Water Samples". Sensors 18, nr 8 (3.08.2018): 2537. http://dx.doi.org/10.3390/s18082537.

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The well-dispersive and superparamagnetic Fe3O4-nanocrystals (Fe3O4-NCs) which could significantly enhance the anodic electrochemiluminescence (ECL) behavior of luminol, were synthesized in this study. Compared to ZnS, ZnSe, CdS and CdTe nanoparticles, the strongest anodic ECL signals were obtained at +1.6 V on the Fe3O4-NCs coated glassy carbon electrode. The ECL spectra revealed that the strong ECL resonance energy transfer occurred between luminol and Fe3O4-NCs. Furthermore, under the optimized ECL experimental conditions, such as the amount of Fe3O4-NCs, the concentration of luminol and the pH of supporting electrolyte, BPA exhibited a stronger distinct ECL quenching effect than its structural analogs and a highly selective and sensitive ECL sensor for the determination of bisphenol A (BPA) was developed based on the Fe3O4-NCs. A good linear relationship was found between the ECL intensity and the increased BPA concentration within 0.01–5.0 mg/L, with a correlation coefficient of 0.9972. The detection limit was 0.66 × 10−3 mg/L. Good recoveries between 96.0% and 105.0% with a relative standard deviation of less than 4.8% were obtained in real water samples. The proposed ECL sensor can be successfully employed to BPA detection in environmental aqueous samples.

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Patnaik, Sumanta Kumar, Sukanta Kumar Triapthy i Surendra Nath Sahu. "Synthesis and characterization of small size fluorescent LEEH caped blue emission ZnTe quantum dots". Materials Science-Poland 35, nr 1 (23.04.2017): 1–5. http://dx.doi.org/10.1515/msp-2017-0012.

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AbstractWe report here for the first time the synthesis of LEEH caped very small size (2 nm) ZnTe quantum dots at low temperature (less than 100 °C) using a simple chemical route. The effects of aging and stirring time on the absorption spectra of the quantum dots were investigated. The synthesized nanocrystal (NC) was characterized by PL, TEM, XRD and the formation of very small size quantum dots having FCC structure was confirmed. Further, blue emission from the prepared sample was observed during exposure to monochromatic UV radiation. ZnTe NCs obtained in this study were found to be more stable compared to those presented in literature reports. ZnTe NCs may be considered as a new material in place of CdTe for optoelectronics devices.

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Marandi, M., i F. S. Mirahmadi. "Aqueous synthesis of the CdTe NCs and influence of size on photovoltaic performance of the CdS/CdTe co-sensitized solar cells". Journal of Alloys and Compounds 800 (wrzesień 2019): 140–49. http://dx.doi.org/10.1016/j.jallcom.2019.06.025.

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Maiti, Sourav, Tushar Debnath, Partha Maity i Hirendra N. Ghosh. "Tuning the Charge Carrier Dynamics via Interfacial Alloying in Core/Shell CdTe/ZnSe NCs". Journal of Physical Chemistry C 120, nr 3 (12.01.2016): 1918–25. http://dx.doi.org/10.1021/acs.jpcc.5b09904.

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Schneider, R., F. Weigert, V. Lesnyak, S. Leubner, T. Lorenz, T. Behnke, A. Dubavik i in. "pH and concentration dependence of the optical properties of thiol-capped CdTe nanocrystals in water and D2O". Physical Chemistry Chemical Physics 18, nr 28 (2016): 19083–92. http://dx.doi.org/10.1039/c6cp03123d.

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The optical properties of semiconductor nanocrystals (SC NCs) are largely controlled by their size and surface chemistry, i.e., the chemical nature and number of surface ligands as well as the strength of the particle-ligand bond.

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Wang, Yan-Qin, Tong Zhao, Xi-Wen He, Wen-You Li i Yu-Kui Zhang. "A novel core-satellite CdTe/Silica/Au NCs hybrid sphere as dual-emission ratiometric fluorescent probe for Cu2+". Biosensors and Bioelectronics 51 (styczeń 2014): 40–46. http://dx.doi.org/10.1016/j.bios.2013.07.028.

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SHEN, M. Y., M. ODA, T. GOTO i T. YAO. "DYNAMICAL PROCESS OF PHOTOIONIZATION IN SEMICONDUCTOR NANOCRYSTALS". International Journal of Modern Physics B 15, nr 28n30 (10.12.2001): 3574–78. http://dx.doi.org/10.1142/s0217979201008184.

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When quantum dots (QDs) or nanocrystals (NCs) are photoionized, great changes of electric fields exerted on QDs occur, then photodarkening, photobrightening, and persistent hole burning effects may be macroscopically observed in QD system, and luminescence spectral diffusion and on/off behavior may be microscopically observed in a single QD. The dynamics of the emitted carrier from the QD by photoionization governs the properties of these phenomena. The photoionization process has been directly found in CdTe nanocrystals embedded in TOPO by measuring the temperature dependence of their photocurrent and photoluminescence. The phase transition of the matrix TOPO from amorphous solid to liquid makes the diffusion length of the emitted carriers outside the nanocrystals increase abruptly, resulting in a steep rise in both the photocurrent and the photoluminescence. Photoionization of a QD is fundamentally important to its optical properties

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Sun, Haizhu, Hao Zhang, Junhu Zhang, Haotong Wei, Jie Ju, Minjie Li i Bai Yang. "White-light emission nanofibers obtained from assembling aqueous single-colored CdTe NCs into a PPV precursor and PVA matrix". Journal of Materials Chemistry 19, nr 37 (2009): 6740. http://dx.doi.org/10.1039/b909089d.

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Carvalho, A. F., D. M. Silva, S. S. Azevedo, R. M. Piatti, M. E. Genovez i E. Scarcelli. "Detecção dos genes da toxina citoletal distensiva em estirpes de Campylobacter jejuni isoladas de carcaças de frangos". Arquivo Brasileiro de Medicina Veterinária e Zootecnia 62, nr 5 (październik 2010): 1054–61. http://dx.doi.org/10.1590/s0102-09352010000500006.

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Foram analisadas 80 amostras de sobrecoxas de frangos de corte resfriados provenientes de feiras livres e hipermercados do município de São Paulo, SP. Treze estirpes de Campylobacter spp. foram isoladas em 10 (12,5%) sobrecoxas, sendo cinco amostras originárias de feiras livres e cinco de hipermercados. Onze estirpes foram identificadas como Campylobacter jejuni e duas como Campylobacter coli. As 11 estirpes foram confirmadas como C. jejuni pela PCR do gene da hipuricase (hip), e destas, quatro (36,4%) apresentaram os três genes (cdtA, cdtB e cdtC) codificantes da toxina citoletal distensiva pela multiplex-PCR, sendo três estirpes provenientes de hipermercados e uma de feira livre. Observou-se a presença de estirpes virulentas de C. jejuni, portadoras do complexo de genes cdt, nas amostras de frango resfriado, não só na linha de abate, mas até o ponto final da cadeia de distribuição, nos dois principais centros de venda a varejo.

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Dias, P. A., T. P. Moraes, D. E. Wilsmann, M. M. Ferrasso, M. F. Marinheiro, J. G. Heinen, C. I. P. Calabuig i C. D. Timm. "Ocorrência de Campylobacter e Enterobacteriaceae em aves silvestres e frangos de corte". Arquivo Brasileiro de Medicina Veterinária e Zootecnia 71, nr 1 (luty 2019): 225–31. http://dx.doi.org/10.1590/1678-4162-10289.

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RESUMO As aves silvestres podem ser reservatório de bactérias patogênicas e atuar como veiculadoras desses microrganismos para o ambiente, os animais domésticos e o homem. Portanto, o objetivo deste trabalho foi verificar a ocorrência de Campylobacter spp., Yersinia enterocolitica e Salmonella enterica em aves silvestres capturadas nas áreas próximas de aviários e em frangos de corte alojados nesses estabelecimentos, além de verificar a presença dos genes cdtA, cdtB e cdtC nos isolados de Campylobacter e identificar os sorotipos de Salmonella encontrados. Amostras de fezes de 189 aves silvestres capturadas com redes de neblina nas áreas próximas de 10 aviários e de 200 frangos de corte foram processadas para pesquisa de Campylobacter spp., S. enterica e Y. enterocolitica. Duas espécies de aves silvestres, Sicalis flaveola (canário-da-terra) e Zonotrichia capensis (tico-tico), foram positivas para Salmonella e Campylobacter, respectivamente. Foram isolados Campylobacter spp., S. enterica e Y. enterocolitica de frangos. Todos os isolados de Campylobacter analisados apresentaram os genes cdt. Em dois aviários, Campylobacter foi isolado tanto de frangos como de aves silvestres, entretanto a contaminação mútua entre essas aves não foi comprovada. Este foi o primeiro relato de isolamento de Campylobacter de Z. capensis e de Salmonella do sorotipo Derby de S. flaveola.

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Zhou, Wu Lei, Tuo Cai, Jian Xiao, Xue Ting Han, Jian Bo Liu, Liang Xu, Jian Guang Chi, Shao Hong Gao, Xi Ping Cai i Li Min An. "Charge Transfer and Energy Transfer between CdSe Semiconductor Nano Crystals and Polyaniline Molecule". Advanced Materials Research 981 (lipiec 2014): 801–5. http://dx.doi.org/10.4028/www.scientific.net/amr.981.801.

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CdSe semiconductor nano crystals (NCs) and Polyaniline (PAni) are mixed uniformly to prepare CdSe NCs/PAni complex. PAni can quench the fluorescent signal of CdSe NCs. The fluorescent intensity of CdSe NCs/PAni complex is related to the size of CdSe NCs and concentration of PAni. Ultraviolet visual (UV-Vis) absorption spectra and fluorescence spectra are employed to analysis the quenching phenomenon. The mechanism of fluorescence quench is dependent on two factors: on one hand, the FÖrster resonance energy transfer conducts from CdSe to PAni; on the other hand, PAni can intercept the electron charge of CdSe and lead to the interruption of radiative recombination.

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Zhou, Wu Lei, Tuo Cai, Yun Chen, Xuan Lin Chen, Yu Qiu Qu, Xing Bin Huang, Wen Jiang Dai i in. "Synthesis of CdS-Capped CdSe Nanocrystals without any Poisonous Materials". Advanced Materials Research 981 (lipiec 2014): 806–9. http://dx.doi.org/10.4028/www.scientific.net/amr.981.806.

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CdS-capped CdSe nanocrystals (NCs) which show high luminescence quantum yield are synthesized without any Poisonous Materials in aqueous solution. The synthesis in an aqueous medium without any poisonous materials is attached importance to. The absorption spectroscopy and photoluminescence spectroscopy are employed to analyze the NCs. It takes 78s that the intensity decreases to the half for bare CdSe NCs, but 442s for CdSe/CdS core/shell NCs. The photo stability of CdSe NCs under 325nm laser irradiation is enhanced greatly after CdS overcoating.

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Jin, Yu Juan, Yun Jun Luo, Guo Zhi Xu i Biao Yang. "Effects of Metallic Ions on Photoluminescence Properties of CdSe/PAMAM Nanocomposites and their Application in Fingerprint Detection". Advanced Materials Research 295-297 (lipiec 2011): 900–906. http://dx.doi.org/10.4028/www.scientific.net/amr.295-297.900.

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Uniform and well-dispersed photoluminescent semiconductor CdSe(Cadmium selenium) QDs(Quantum dots) werein-situprepared stabilized by G4.0-NH2PAMAM dendrimers in water and effects of metallic ions such as Zn2+, Cd2+, Cu2+, Ag+, Pb2+, K+, Na+on the photoluminescence(PL) properties of CdSe QDs were studied using spectrophotometric titration. The results show that Zn2+and Cd2+ions enhance the PL intensity of CdSe QDs, Cu2+, Ag+and Pb2+ions quench the PL intensity, while K+and Na+ions have no obvious effects. Those are attributed to the surface modification of CdSe QDs. Excess Cd2+ions can reduce the non-combination centers, increase the passivation of PAMAM on the surface of CdSe QDs, and form a Schottky-like barrier which enhanced the PL efficiency. Excess Zn2+ions can also increase the PL intensity of CdSe QDs in the same way as Cd2+ions because of the much similar lattice parameters of CdSe and ZnSe. However, a CuSe, Ag2Se or PbSe shell on CdSe QDs emerges due to the substitution of Cd2+ions, which leads to the decrease of band-edge emmiting of CdSe QDs. And the quenching effect of Ag+is stonger than Cu2+and Pb2+because of the lower solubility of Ag2Se formed on the surface of CdSe QDs. Oil latent fingerprints deposited on tinfoil surface treated with CdSe/dendrimer NCs(Nanocomposites)、Cd2+-CdSe/ PAMAM NCs and Zn2+-CdSe /PAMAM NCs emitted bright yellow photoluminescence under ultraviolet excitation of 365nm from an UV LED in the dark., among, fingerprint treated with Cd2+-CdSe/dendrimer NCs and Zn2+-CdSe /PAMAM NCs was detected with better resolving rate.

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Otazhonov, S. M., R. N. Ergashev, K. A. Botirov, B. A. Qaxxorova, M. A. Xudoynazarova, N. A. Abdukarimova, M. E. Madaminova i E. M. Ismoilova. "Influence of thickness and temperature on photoelectric properties of p-CdTe-nCdS and pCdTe-CdSe heterostructures". Journal of Physics: Conference Series 2388, nr 1 (1.12.2022): 012001. http://dx.doi.org/10.1088/1742-6596/2388/1/012001.

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Abstract In this paper, we study the photoelectric properties of pCdTe-nCdS and pCdTe-nCdSe-based film heterostructures. It is shown that the high value of the electron diffusion length in pCdTe slick (pellicle) is due to the presence of a built-in field in it. When studying the effect of temperature on the spectral characteristics, it was found that with increasing temperature, the maximum photosensitivity of the heterostructure shifts towards longer wavelengths of light. The shift in the photosensitivity maximum is explained by changes in the band gap of cadmium telluride. As shown, the accumulation coefficient increases with raising thickness of the wide-gap layer. It has been established that the short-wavelength edge of the photosensitivity of the pCdTe-nCdS structure begins to increase sharply at a photon energy of hv ≤ 2,3 eV, while the photosensitivity of the pCdTe-nCdSe structure already at a photon energy has a significant value ~ 100 μA/mV.

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Das, Kishan, Neelima Bhatt, Ajith Manayil Parambil, Kajal Kumari, Raj Kumar, Kamla Rawat, Paulraj Rajamani i in. "Divergent Responses of Hydrophilic CdSe and CdSe@CdS Core–Shell Nanocrystals in Apoptosis and In Vitro Cancer Cell Imaging: A Comparative Analysis". Journal of Functional Biomaterials 14, nr 9 (1.09.2023): 448. http://dx.doi.org/10.3390/jfb14090448.

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With their distinctive core–shell design, core–shell nanocrystals have drawn interest in catalysis, medicinal research, and nanotechnology. These nanocrystals have a variety of characteristics and possible uses. The application of core–shell nanocrystals offers significant potential in increasing diagnostic and therapeutic approaches for cancer research in apoptosis and in vitro cancer cell imaging. In the present study, we investigated the fluorescence behavior of hydrophilic CdSe (core-only) and CdSe@CdS (core–shell) nanocrystals (NCs) and their potential in cancer cell imaging. The addition of a CdS coating to CdSe NCs increased the fluorescence intensity tenfold. The successful fabrication of core–shell CdSe@CdS nanocrystals was proven by a larger particle size (evaluated via DLS and TEM) and their XRD pattern and surface morphology compared to CdSe (core-only) NCs. When these NCs were used for bioimaging in MCF-7 and HEK-293 cell lines, they demonstrated excellent cellular uptake due to higher fluorescence intensity within cancerous cells than normal cells. Comparative cytotoxicity studies revealed that CdSe NCs were more toxic to all three cell lines (HEK-293, MCF-7, and HeLa) than CdSe@CdS core–shell structures. Furthermore, a decrease in mitochondrial membrane potential and intracellular ROS production supported NCs inducing oxidative stress, which led to apoptosis via the mitochondria-mediated pathway. Increased cytochrome c levels, regulation of pro-apoptotic gene expression (e.g., p53, Bax), and down-regulation of Bcl-2 all suggested cellular apoptosis occurred via the intrinsic pathway. Significantly, at an equivalent dose of core–shell NCs, core-only NCs induced more oxidative stress, resulting in increased apoptosis. These findings shed light on the role of a CdS surface coating in reducing free radical release, decreasing cytotoxicity, and improving fluorescence, advancing the field of cell imaging.

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Kadim, Akeel M. "Colloidal Synthesis of CdSe Nanocrystals: Preparation, Characterization in Different Organic Solvent". Nano Hybrids and Composites 29 (czerwiec 2020): 1–7. http://dx.doi.org/10.4028/www.scientific.net/nhc.29.1.

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Colloidal CdSe Nanocrystals (NCs) or quantum dots (QDs) have been developed using a yielding solution technique utilizing chemical reactions in chloroform and oleic acid in different organic solvents. This assembly is an improvement of the systematic thermal decomposition of high temperature organic solvent compounds. CdSe NCs of specific sizes can be produced easily by adjusting the solvent. This technique is reproducible and clear, so industrial development can be easily scaled up. Characterization at room temperature of the UV-Vis absorption and Photoluminescence (PL) spectra. Results reveal that the CdSe prepared with the creation of defects was nanocrystalline. The energy difference (Eg) measured in PL was 2.3 and 2.69 eV respectively for CdSe NCs in chloroform and oleic acid. The structures of the CdSe quantum dots were determined by scanning electron microscopy (SEM). The phase-transfer of chloroform and oleic acid stabilized CdSe nanocrystals solutions was studied for their potentials in white light generation applications.

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Zhou, Bo, Guanjun Xiao, Xinyi Yang, Quanjun Li, Kai Wang i Yingnan Wang. "Pressure-dependent optical behaviors of colloidal CdSe nanoplatelets". Nanoscale 7, nr 19 (2015): 8835–42. http://dx.doi.org/10.1039/c4nr07589g.

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Silva Costa, Suellen Caroline, Antônia Sônia Alves Cardoso Diniz, Vinícius Camatta i Lawrence Lee Kazmerski. "DETERMINAÇÃO DAS TAXAS DE SUJIDADE PARA MÓDULOS FOTOVOLTAICOS DE FILME FINO E SILÍCIO CRISTALINO INSTALADOS EM DIFERENTES ZONAS CLIMÁTICAS BRASILEIRAS". Revista Brasileira de Energia Solar 11, nr 1 (31.05.2021): 58–67. http://dx.doi.org/10.59627/rbens.2020v11i1.298.

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O acúmulo de sujidades sobre módulos fotovoltaicos (FV) induz na redução do desempenho destes dispositivos, podendo ser ainda mais agravante em regiões consideradas atrativas para a aplicação dessa tecnologia, onde a irradiância apresenta elevados índices ao longo do ano, porém sob predominância de clima seco e árido propício para a deposição de sujidades. Os efeitos do acúmulo de sujeira no desempenho dos módulos FV são específicos para cada localidade, uma vez que o comportamento da deposição e a composição físico-química dos contaminantes são influenciados por um conjunto de variáveis específicas do local de instalação dos módulos fotovoltaicos. Neste cenário, este artigo apresenta uma metodologia para quantificar a taxa de sujidade (“Soiling Ratio” – SRatio) e a relação de sujidade diária (“Soiling Rate” – SRate) em módulos FV de telureto de cádmio (CdTe) e silício policristalino (p-Si) através de medições realizadas em estações de monitoramento instaladas em diferentes zonas climáticas do Brasil. Os resultados obtidos neste trabalho indicaram: (1) Belo Horizonte/MG (latitude - 19,92°, longitude -43,99°), um SRatio médio para o período de análise de 0,94 para telureto de cádmio (CdTe) e 0,92 para silício policristalino (p-Si); (2) Porto Alegre/RS, (Latitude -30,05 °, Longitude -51,17 °), um SRatio em torno de 0,97 e 0,98 para as tecnologias CdTe e p-Si, respectivamente; e (3) Brotas de Macaúbas/BA (Latitude -11,99°, Longitude -42,62°), SRatio de 0,99 e 0,95 para as tecnologias CdTe e p-Si, respectivamente. A partir das características do SRatio, os dados do período seco foram utilizados para estimar o SRate através do estimador Theil-Sen, resultando em valores médios de -0,20%/dia para o CdTe e -0,14%/dia para Belo Horizonte/MG. O maior SRate para tecnologia CdTe pode ser justificado devido a diferença nas respostas espectrais das duas tecnologias FV, pois a sujeira tem um impacto maior nas tecnologias fotovoltaicas de menor comprimento de onda.

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Chung, Shu-Ru, Hong-Shuo Chen, Chen-Yu Chien, Meng-Yi Bai i Kuan-Wen Wang. "The Promotion of the Efficiency of Organic Photovoltaic Devices by Addition of Anisotropic CdSe Nanocrystals". International Journal of Photoenergy 2014 (2014): 1–8. http://dx.doi.org/10.1155/2014/219123.

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CdSe nanocrystals (NCs) with different morphologies have been synthesized and applied as the acceptor in the active layer of the organic photovoltaic (OPV) devices. CdSe tetrapod (TP)/nanorod (NR) with zinc-blended seeds and wurtzite arms is prepared by seed growth method and mixed with poly(3-hexylthiophene) (P3HT): [6,6]-phenyl-C61-butyric acid methyl ester (PCBM). When the concentrations of CdSe in P3HT: PCBM system are 50 wt% optimally, the efficiency can be promoted about 4.3%, suggesting that an enhancement of 13.2% can be obtained and the addition of anisotropic CdSe NCs content in the active layer can be beneficial for the transport of electrons and light absorption in the OPV devices.

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Zeevi, Gilad, Joanna Dehnel, Adam K. Budniak, Yana Milyutin, Guy Ankonina, Hossam Haick, Efrat Lifshitz i Yuval E. Yaish. "Dynamics of light-induced charge transfer between carbon nanotube and CdSe/CdS core/shell nanocrystals". Nano Futures 6, nr 1 (20.01.2022): 015001. http://dx.doi.org/10.1088/2399-1984/ac3ccc.

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Abstract The integration of semiconducting colloidal nanocrystals (NCs) with carbon nanotubes (CNTs) in a single device presents a unique platform that combines optical flexibility with high charge carrying capability. These qualities are desirable in many applications such as photovoltaic cells, photocatalysis, and light sensors. Here, we present hybrid devices that incorporate various CdSe/CdS core/shell NCs, such as seeded quantum dots and asymmetric seeded nanorods (a-sNRs), with a single-wall CNT in a field-effect transistor geometry. We used electrical measurements to probe a light-induced charge transfer (LICT) between the CdSe/CdS NCs and the CNT. We investigate the effect of gate voltage on the LICT magnitude and temporal characteristics. Surprisingly, the measured photo-response depends on the gate voltage, and we observe both electrons and holes transfer from the a-sNRs to the CNT. Furthermore, a comparison between LICT measurements on different devices with different CNTs and NC types reveals that the charge transfer time is directly proportional to the shell-thickness around the CdSe core and inversely correlated with the NCs size. The recovery of the charge trapped inside the CdSe/CdS NCs is characterized by two distinct fast and slow relaxation times, which depend on the NCs size and CNT type. Although, the charge relaxation time is similar between the symmetric QDs and the asymmetric sNRs, the overall percentage of the remaining charge in the QDs is significantly larger than in the sNRs. Understanding both gate voltage and NCs size effect on the LICT processes can optimize the performance of optoelectronic devices.

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Sachdeva, Megha, P. Agrawal, Sheenam Sachdeva, K. K. Bhasin, S. K. Tripathi i Shivani Gulati. "Synthetic Route of CdSe Nanocrystalline Films Fabricated by Substrate Vibration Assisted Drop Casting Method". Advanced Science, Engineering and Medicine 12, nr 6 (1.06.2020): 761–70. http://dx.doi.org/10.1166/asem.2020.2620.

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Herein, we report a greener, non-toxic, cost effective and a modest scheme for the fabrication of excellent CdSe nanocrystals (NCs). Precursors for the present reaction are synthesized by the treatment of cadmium chloride (CdCl2) with 2-pyridyl selenolate (NaSeC5H4N) resulting a complex of the formula [(C5H4NSe)2Cd]. The complex is characterized by NMR (1H and 13C) and IR spectroscopies. The complex, [(C5H4NSe)2Cd] is found to be polymeric in nature, as indicated by its insolubility in solvents, and is further customized as a single-source pioneers for the preparation of colloidal CdSe NCs. Thermolysis of [(C5H4NSe)2 Cd] has been successfully carried out by hotinjection method using low-cost and harmless oleic acid (OA) as the coordinating solvent, thereby rejecting the need of air-sensitive and toxic solvents. Based upon dynamic light scattering (DLS) technique, the average size of colloidal CdSe NCs are determined using particle size analyzer. The average size of colloidal NCs comes out to be 6.3 nm. Thin films of colloidal CdSe NCs are deposited on glass substrate using drop-casting (DC) and ultrasonic substrate vibration assisted drop casting (SVADC) methods to study their use as workable materials for engineering devices. The films are characterized by ultraviolet-visible spectroscopy (UV-vis), photoluminescence (PL) studies, X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques.

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Li, Kai-Le, Yun-Hu Zhang, Rui Xing, Yan-Feng Zhou, Xue-Dong Chen, Hao Wang, Bin Song, Yang-Hu Sima, Yao He i Shi-Qing Xu. "Different toxicity of cadmium telluride, silicon, and carbon nanomaterials against hemocytes in silkworm, Bombyx mori". RSC Adv. 7, nr 79 (2017): 50317–27. http://dx.doi.org/10.1039/c7ra09622d.

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Zappia, Stefania, Silvia Destri, Marinella Striccoli, Maria Lucia Curri, A. Evelyn di Mauro, Zoobia Ameer, Giuseppe Maruccio, Aurora Rizzo i Rosanna Mastria. "Morphological Study of CdSe Nanocrystals Passivated with a Low Band Gap Rod-Coil Diblock Copolymer for Hybrid Solar Cells". Advances in Science and Technology 93 (październik 2014): 235–40. http://dx.doi.org/10.4028/www.scientific.net/ast.93.235.

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Different nanocomposite materials consisting of semiconducting CdSe nanocrystals (NCs) and a low band gap copolymer poly[2,6-(4,4-bis-(2-ethylhexyl)-4H-cyclopenta[2,1-b:3.4-b’]dithiophene)-alt-4,7-(2,1,3-benzothiadiazole)] (PCPDTBT) were prepared, morphologically characterized, and tested in hybrid solar cells. In addition, a PCPDTBT-based rod-coil diblock copolymer was synthesized through a grafting-onto approach and a preliminary evaluation of the morphology of the hybrid nanocomposites with CdSe NCs was performed.

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Yang, Boping, Huichao Zhang i Jiayu Zhang. "Copper Acetate Etching of Colloidal CdSe Nanocrystals". Nano 11, nr 02 (luty 2016): 1650021. http://dx.doi.org/10.1142/s1793292016500211.

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Colloidal CdSe nanocrystals (NCs) were etched after Se/TBP and Zinc stearate/ODE were injected into the mixture of as-prepared CdSe NCs and Copper (II) acetate in ODE solvent. Spectroscopic and structural investigations demonstrate the etching process. Along with the etching time, both the absorption and photoluminescence (PL) spectra of etched NCs showed blue-shift while the transmission electron microscopy (TEM) images indicated that the size of the NCs became from 5.6[Formula: see text]nm to 2.6[Formula: see text]nm. X-ray diffraction (XRD) patterns suggested that no other clusters or core/shell NCs were formed in the etching process and inductively coupled plasma (ICP) data demonstrated that only selenium and cadmium comprised the etched NCs. Electronic paramagnetic resonance (EPR) spectra indicated the deoxidization of Cu[Formula: see text] ions and suggested the etching mechanism through cation exchange process.

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