Preparation of Photoluminescent ZnSe/PAMAM Nanocomposites

2014 ◽  
Vol 1044-1045 ◽  
pp. 92-95
Author(s):  
Yu Juan Jin ◽  
Teng Zhang ◽  
Mu Nan Qiu ◽  
Ting Ting Zhao ◽  
Kai Li Jiang ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Absorption Spectra ◽  
Emission Spectra ◽  
Pamam Dendrimers ◽  
Molar Ratio ◽  
Polyamidoamine Dendrimers ◽  
Pl Emission

Uniform and well-dispersed photoluminescent semiconductor ZnSe (zinc selenium) QDs (Quantum dots) were in-situ prepared stabilized by G4.0-NH3+PAMAM(polyamidoamine) dendrimers in methanol. The properties of ZnSe QDs encapsulated in PAMAM dendrimers were characterized by UV-Vis absorption spectra and photoluminescence (PL) emission spectra. The results were: ZnSe/PAMAM NCs (nanocomposites) with molar ratio 15 emitted strongest fluorescence.

Photoluminescent Characteristics of ZnS Quantum Dots Synthesized in Non-Aqueous-Phase

2013 ◽  
Vol 750-752 ◽  
pp. 991-994
Author(s):  
Jing Liu ◽  
Ming Ying ◽  
Yu Ling Tan ◽  
Bo Xi
Keyword(s):  
Aqueous Solution ◽  
Quantum Dots ◽  
Quantum Yield ◽  
Reaction Medium ◽  
Emission Spectra ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
Zinc Blend ◽  
Red Emission ◽  
X Ray

ZnS quantum dots (ZnS QDs) synthesized in aqueous solution is easy to gather a mass, which always results in low quantum yield. So, in this study benzene was used as reaction medium in which ZnS QDs with different hues were synthesized, and the hues of ZnS QDs were depend on the molar ratio of Zn (CH3COO)2 and Na2S·9H2O. The results show the emission spectra of ZnS QDs shifts with the change of the precursor molar ratio but the absorption peak at 310nm is not. The emission peaks centered at 430nm and 580nm at higher molar ratio [Zn2+]/[S2-] with blue-violet emitting phosphors; but, ZnS QDs synthesized at higher molar ratio [S2-]/[Zn2+] have orange-red emission at 580nm only. The X-ray diffraction analysis shows the crystallinity of ZnS QDs is better at [Zn2+]/[S2-]=1:10, which are typical zinc blend with nanorod structure.

Synthesis of CdTe and CdTe/CdS Core-Shell Quantum Dots and their Optical Properties

2011 ◽  
Vol 306-307 ◽  
pp. 1350-1353 ◽  
Author(s):  
Juan Juan Lu ◽  
Shen Guang Ge ◽  
Fu Wei Wan ◽  
Jing Hua Yu
Keyword(s):  
Quantum Dots ◽  
Thioglycolic Acid ◽  
Water Soluble ◽  
Molar Ratio ◽  
Core Shell ◽  
The Core ◽  
Cdte Qds ◽  
Quality Water ◽  
Synthesis Procedure ◽  
Pl Emission

This paper describes the synthesis of CdTe and CdTe/CdS core-shell quantum dots (QDs) in aqueous solution. The quantum dots are prepared by using thioglycolic acid (TGA) as stabilizers. The synthesis procedure is simple and controllable. Different sized CdTe QDs with tuned PL wavelengths from 550 to 640 nm was synthesized by controlling reaction time within 5 h in aqueous solutions at a temperature of 100 °C. We also investigated the influence of precursor Cd/Te molar ratio for the prepared QDs. It was showed that the core-shell CdTe/CdS QDs have larger photoluminescence (PL) emission intensity than the original CdTe QDs. The synthesized core-shell CdTe/ZnS QDs have high quality, water-soluble and will be useful in applications of biolabeling, biosensing, and imaging.

Aged Fingermarks Detection with CdS/PAMAM Nanocomposites

2011 ◽  
Vol 282-283 ◽  
pp. 466-469 ◽  
Author(s):  
Yu Juan Jin ◽  
Yun Jun Luo ◽  
Guo Zhi Xu ◽  
Biao Yang
Keyword(s):  
Quantum Dots ◽  
Cadmium Sulfide ◽  
Pamam Dendrimers ◽  
Adhesive Tape ◽  
Yellow Luminescence ◽  
Ultraviolet Excitation ◽  
Nano Scale ◽  
Powder Suspension ◽  
Cds Qds

CdS(Cadmium sulfide)/PAMAM(polyamidoamine) Nanocomposites were in-situ prepared taking PAMAM dendrimers as stabilization in water. The prepared solution containing photoluminescent semiconductor CdS QDs(Quantum dots) was utilized for detection of aged fingermarks on adhesive tape strips. The fingermarks were aged for 1 d, 7 d and 30 d in nature light respectively. The results show that the latent aged fingermarks treated with CdS/PAMAM nanocomposites emit yellow luminescence under ultraviolet excitation of 365 nm in the dark. Aged fingermarks were detected successfully with better resolving rate comparing with existing nano-scale commercial TiO2powder suspension.

Effect of Solvent to Fingerprint Detection by Photoluminescent CdSe/PAMAM Nanocomposites

2013 ◽  
Vol 744 ◽  
pp. 319-322
Author(s):  
Yu Juan Jin ◽  
Yun Jun Luo ◽  
Yuan Feng Wang ◽  
Hui Sun ◽  
Hao Nan Zhang ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Yellow Emission ◽  
Cdse Qds ◽  
Latent Fingerprints ◽  
Effect Of Solvent ◽  
Polyamidoamine Dendrimers ◽  
Oil Components ◽  
Cadmium Selenium ◽  
Fingerprint Detection

Uniform and well-dispersed photoluminescent semiconductor CdSe (Cadmium selenium) QDs (Quantum dots) were in-situ prepared by taking G4.0-NH2PAMAM(polyamidoamine) dendrimers as inner templates in water and methanol respectively. The prepared solutions containing photoluminescent semiconductor CdSe QDs were utilized for detection of unfumed oil fingerprints on tinfoil. The results show that unfumed latent fingerprints treated with prepared CdSe/PAMAM nanocomposites both displayed yellow emission and the latent fingerprints were detected clearly, while treated with CdSe/PAMAM composites in water manifested stronger emission compared with those treated with CdSe/PAMAM composites in methanol; Also, the veins of fingerprints treated with CdSe/PAMAM nanocomposites in methanol became slim because of the dissolution of methanol to oil components in fingerprints.

scholarly journals Structural and Photoluminescence Investigations of Tb3+/Eu3+ Co-Doped Silicate Sol-Gel Glass-Ceramics Containing CaF2 Nanocrystals

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 754
Author(s):  
Natalia Pawlik ◽  
Barbara Szpikowska-Sroka ◽  
Tomasz Goryczka ◽  
Joanna Pisarska ◽  
Wojciech A. Pisarski
Keyword(s):  
Sol Gel ◽  
Glass Ceramics ◽  
Emission Spectra ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
Co Doping ◽  
Near Ultraviolet ◽  
Transmission Electron ◽  
Co Doped

In this work, the series of Tb3+/Eu3+ co-doped xerogels and derivative glass-ceramics containing CaF2 nanocrystals were prepared and characterized. The in situ formation of fluoride crystals was verified by an X-ray diffraction technique (XRD) and transmission electron microscopy (TEM). The studies of the Tb3+/Eu3+ energy transfer (ET) process were performed based on excitation and emission spectra along with luminescence decay analysis. According to emission spectra recorded under near-ultraviolet (NUV) excitation (351 nm, 7F6 → 5L9 transition of Tb3+), the mutual coexistence of the 5D4 → 7FJ (J = 6–3) (Tb3+) and the 5D0 → 7FJ (J = 0–4) (Eu3+) luminescence bands was clearly observed. The co-doping also resulted in gradual shortening of a lifetime from the 5D4 state of Tb3+ ions, and the ET efficiencies were varied from ηET = 11.9% (Tb3+:Eu3+ = 1:0.5) to ηET = 22.9% (Tb3+:Eu3+ = 1:2) for xerogels, and from ηET = 25.7% (Tb3+:Eu3+ = 1:0.5) up to ηET = 67.4% (Tb3+:Eu3+ = 1:2) for glass-ceramics. Performed decay analysis from the 5D0 (Eu3+) and the 5D4 (Tb3+) state revealed a correlation with the change in Tb3+–Eu3+ and Eu3+–Eu3+ interionic distances resulting from both the variable Tb3+:Eu3+ molar ratio and their partial segregation in CaF2 nanophase.

scholarly journals Carbon Nitride Quantum Dots Modified TiO2 Inverse Opal Photonic Crystal for Solving Indoor VOCs Pollution

Catalysts ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 464
Author(s):  
Jie Yu ◽  
Angel Caravaca ◽  
Chantal Guillard ◽  
Philippe Vernoux ◽  
Liang Zhou ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Carbon Nitride ◽  
Sol Gel ◽  
Green Energy ◽  
Inverse Opal ◽  
Oxidation Reactions ◽  
Composite Photocatalyst ◽  
Colloidal Photonic Crystals ◽  
Inverse Opal Structure

Indoor toxic volatile organic compounds (VOCs) pollution is a serious threat to people’s health and toluene is a typical representative. In this study, we developed a composite photocatalyst of carbon nitride quantum dots (CNQDs) in situ-doped TiO2 inverse opal TiO2 IO for efficient degradation of toluene. The catalyst was fabricated using a sol-gel method with colloidal photonic crystals as the template. The as-prepared catalyst exhibited excellent photocatalytic performance for degradation of toluene. After 6 h of simulated sunlight irradiation, 93% of toluene can be converted into non-toxic products CO2 and H2O, while only 37% of toluene is degraded over commercial P25 in the same condition. This greatly enhanced photocatalytic activity results from two aspects: (i) the inverse opal structure enhances the light harvesting while providing adequate surface area for effective oxidation reactions; (ii) the incorporation of CNQDs in the framework of TiO2 increases visible light absorption and promotes the separation of photo-generated charges. Collectively, highly efficient photocatalytic degradation of toluene has been achieved. In addition, it can be expanded to efficient degradation of organic pollutants in liquid phase such as phenol and Rhodamine B. This study provides a green, energy saving solution for indoor toxic VOCs removal as well as for the treatment of organic wastewater.

In situ ligand exchange of thiol-capped CuInS2/ZnS quantum dots at growth stage without affecting luminescent characteristics

2011 ◽  
Vol 363 (2) ◽  
pp. 703-706 ◽  
Author(s):  
Hyunki Kim ◽  
Minwon Suh ◽  
Byung-Hwa Kwon ◽  
Dong Seon Jang ◽  
Sung Wook Kim ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Ligand Exchange ◽  
Growth Stage

Au‐Doped Ag 2 Te Quantum Dots with Bright NIR‐IIb Fluorescence for In Situ Monitoring of Angiogenesis and Arteriogenesis in a Hindlimb Ischemic Model

2021 ◽  
pp. 2103953
Author(s):  
Hongchao Yang ◽  
Haoying Huang ◽  
Xiang Ma ◽  
Yejun Zhang ◽  
Xiaohu Yang ◽  
...  
Keyword(s):  
Quantum Dots ◽  
In Situ Monitoring

NIR and Upconversion Luminescence Properties of Nd3+ Doped in Gd2O3-CaO-SiO2-B2O3 Glass System

2014 ◽  
Vol 548-549 ◽  
pp. 124-128 ◽  
Author(s):  
S. Insiripong ◽  
S. Kaewjeang ◽  
U. Maghanemi ◽  
H.J. Kim ◽  
N. Chanthima ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Optical Absorption ◽  
Absorption Spectra ◽  
Upconversion Luminescence ◽  
Emission Spectra ◽  
Concentration Quenching ◽  
Luminescence Spectra ◽  
Optical Absorption Spectra ◽  
Glass Matrices ◽  
Nir Luminescence

In this work, properties of Nd3+ in Gd2O3-CaO-SiO2-B2O3 glass systems with composition 25Gd2O3-10CaO-10SiO2-(55-x)B2O3-xNd2O3 where x = 0.0, 0.5, 1.0, 1.5, 2.0 and 2.5 mol% were investigated. The optical absorption spectra show peaks at 4F3/2 (877 nm) , 4F5/2+2H9/2 (802 nm), 4F7/2+4S3/2 (743 nm), 4F9/2 (682 nm), 2H11/2 (627 nm), 2G7/2 +4G5/2 (582 nm), 4G7/2 +2K13/2 (527 nm), 4G11/2 (481 nm), 2P1/2 (427 nm) and 2L15/2 + 4D1/2 + 1I11/2+ 4D5/2+ 4D3/2 (355 nm) reflecting the Nd3+ ions in glass matrices. The densities were increased with increasing of Nd2O3 concentration. This indicates the increase of the molecular weight by the replacement of B2O3 with a heavier Nd2O3 oxide in the glass. The upconversion luminescence spectra show bands at 393 nm for all Nd2O3 concentration and the strongest intensity from 2.5 % mol of Nd2O3 was obtained. For NIR luminescence, the intensity of Nd3+ emission spectra increases with increasing concentrations of Nd3+ up to 1.5 mol% and beyond 1.5 mol% the concentration quenching is observed.

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