Properties of chemically deposited CdS thin films converted to n-type by indium diffusion

George, P.J.; Sánchez, Alejandro; Nair, P. K.; Huang, Ling

doi:10.1016/0022-0248(95)00318-5

Cited by 12 publications

(8 citation statements)

References 10 publications

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“…Thiourea was used as the precursor of sulfide ions due to its decomposition into S 2− and HS − in water at basic pH levels. [30][31][32][33] The decomposition has a relatively low activation energy, which facilitates the formation of nuclei and regular QDs. 34 The sulfide ions formed in situ react with Cd 2+ to fabricate CdS nuclei, which grows by heating to form CdS NCs (i.e., QDs).…”

Section: Preparation and Characterization Of Cds And Ag 2 S Qdsmentioning

confidence: 99%

Retracted Article: A facile cation exchange-based aqueous synthesis of highly stable and biocompatible Ag₂S quantum dots emitting in the second near-infrared biological window

Gui

Sun

Liu³

et al. 2014

Dalton Trans.

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Second near-infrared (NIR-II) emitting Ag2S quantum dots (QDs) with high stability and biocompatibility were synthesized and developed toward an ideal nanoprobe. This study reports a facile synthesis of NIR-II Ag2S QDs on the basis of cation exchange between visible-emitting CdS QDs and Ag(+) ions in aqueous solution. Experimental data testified that the cation exchange was quick and complete and that the resultant products were single monoclinic Ag2S without CdS QDs. The prepared Ag2S QDs were systematically characterized, showed typical NIR-II emission and high PL stability, and had small diameters (~3.5 nm) and a quantum yield up to 2.3%. The results of cytotoxicity assay suggested that the Ag2S QDs produced negligible effects in altering the cell proliferation or in generating reactive oxygen species, indicating an ultralow cytotoxicity and an excellent biocompatibility. These properties have opened up the possibility of using Ag2S QDs for effective bioimaging applications.

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Section: Preparation and Characterization Of Cds And Ag 2 S Qdsmentioning

confidence: 99%

Retracted Article: A facile cation exchange-based aqueous synthesis of highly stable and biocompatible Ag₂S quantum dots emitting in the second near-infrared biological window

Gui

Sun

Liu³

et al. 2014

Dalton Trans.

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“…Thiourea was selected as precursor of sulfide ions because its decomposition into sulfide or hydrogenosulfide in water at basic pH has a relatively low activation energy, − which is favorable for the formation of nuclei and regular QDs. S 2‑ or HS – anions formed in situ react with the Cd 2+ salt in the solution to form CdS nuclei that grow by heating to form CdS nanocrystals.…”

Section: Resultsmentioning

confidence: 99%

One-Pot Noninjection Route to CdS Quantum Dots via Hydrothermal Synthesis

Aboulaich

Billaud

Abyan

et al. 2012

ACS Appl. Mater. Interfaces

142

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Water-dispersible CdS quantum dots (QDs) emitting from 510 to 650 nm were synthesized in a simple one-pot noninjection hydrothermal route using cadmium chloride, thiourea, and 3-mercaptopropionic acid (MPA) as starting materials. All these chemicals were loaded at room temperature in a Teflon sealed tube and the reaction mixture heated at 100 °C. The effects of CdCl(2)/thiourea/MPA feed molar ratios, pH, and concentrations of precursors affecting the growth of the CdS QDs, was monitored via the temporal evolution of the optical properties of the CdS nanocrystals. High concentration of precursors and high MPA/Cd feed molar ratios were found to lead to an increase in the diameter of the resulting CdS nanocrystals and of the trap state emission of the dots. The combination of moderate pH value, low concentration of precursors and slow growth rate plays the crucial role in the good optical properties of the obtained CdS nanocrystals. The highest photoluminescence achieved for CdS@MPA QDs of average size 3.5 nm was 20%. As prepared colloids show rather narrow particle size distribution, although all reactants were mixed at room temperature. CdS@MPA QDs were characterized by UV-vis and photoluminescence spectroscopy, powder X-ray diffraction, transmission electron microscopy, energy-dispersive X-ray spectrometry and MALDI TOF mass spectrometry. This noninjection one-pot approach features easy handling and large-scale production with excellent synthetic reproducibility. Surface passivation of CdS@MPA cores by a wider bandgap material, ZnS, led to enhanced luminescence intensity. CdS@MPA and CdS/ZnS@MPA QDs exhibit high photochemical stability and hold a good potential to be applied in optoelectronic devices and biological applications.

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“…CdS nanoparticles showing size distribution (shown in Figure c) and with a well-defined crystallinity were prepared by reacting with Cd 2+ and S 2- in DMF. Thiourea was selected as a source of S 2- because it is known to generate S 2- through the thermal decomposition, with the assistance of a base catalyst. − Water included in the cadmium salt as water of crystallization and in DMF leads to hydroxide anion formation in the presence of DMF. The MW-assisted hydrolysis of thiourea catalyzed by hydroxide leads to the release of sulfide anion (S 2- ) in the system .…”

Section: Resultsmentioning

confidence: 99%

Tunable Visible-Light Emission from CdS Nanocrystallites Prepared under Microwave Irradiation

Karan

Mallik

2007

J. Phys. Chem. C

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The microwave (MW)-assisted reaction of cadmium acetate with thiourea in N,N-dimethylformamide (DMF) was controlled by controlling the MW irradiation time in the presence of 1-thioglycerol as a capping agent. The peak position of the absorption band of the CdS nanocrystallites, dispersed in chloroform, shifts toward longer wavelength with increasing MW irradiation time, indicating growth of particle size under prolonged MW irradiation. However, the peak position of absorption band remains at the same wavelength, and only the intensity of the absorption band is increased when the MW irradiation of the colloidal solution of CdS nanocrystallites in DMF is periodically interrupted, keeping the solution at room temperature (27 °C) before each irradiation. This suggests that the particle growth occurs only during the continuous irradiation of MW and stops when the system is cooled down. From the spectral absorption edge, the diameter of CdS nanoparticles has been estimated. Photoluminescence of the CdS nanocrystallites, dispersed in chloroform, observed in the visible range shifts toward higher wavelength with increased duration of MW irradiation. When the MW irradiation was repeated for a fixed duration in colloidal solution of CdS nanocrystallites in DMF, enhancement in PL intensity was noticed without any change in the emission peak position. The relative PL quantum yield of the CdS nanocrystallites was estimated under various experimental conditions. Time-correlated singlephoton counting experiments were performed to study the time-resolved photoluminescence of CdS nanocrystallites. The observed emission decay profiles have been simulated by using the multiexponential model.

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Properties of chemically deposited CdS thin films converted to n-type by indium diffusion

Cited by 12 publications

References 10 publications

Retracted Article: A facile cation exchange-based aqueous synthesis of highly stable and biocompatible Ag₂S quantum dots emitting in the second near-infrared biological window

Retracted Article: A facile cation exchange-based aqueous synthesis of highly stable and biocompatible Ag₂S quantum dots emitting in the second near-infrared biological window

One-Pot Noninjection Route to CdS Quantum Dots via Hydrothermal Synthesis

Tunable Visible-Light Emission from CdS Nanocrystallites Prepared under Microwave Irradiation

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Properties of chemically deposited CdS thin films converted to n-type by indium diffusion

Cited by 12 publications

References 10 publications

Retracted Article: A facile cation exchange-based aqueous synthesis of highly stable and biocompatible Ag2S quantum dots emitting in the second near-infrared biological window

Retracted Article: A facile cation exchange-based aqueous synthesis of highly stable and biocompatible Ag2S quantum dots emitting in the second near-infrared biological window

One-Pot Noninjection Route to CdS Quantum Dots via Hydrothermal Synthesis

Tunable Visible-Light Emission from CdS Nanocrystallites Prepared under Microwave Irradiation

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Retracted Article: A facile cation exchange-based aqueous synthesis of highly stable and biocompatible Ag₂S quantum dots emitting in the second near-infrared biological window

Retracted Article: A facile cation exchange-based aqueous synthesis of highly stable and biocompatible Ag₂S quantum dots emitting in the second near-infrared biological window