scholarly journals Silver Nanoparticle-Mediated Synthesis of Fluorescent Thiolated Gold Nanoclusters

Nanomaterials ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 2835
Author(s):  
Cheng-Yeh Chang ◽  
Tzu-Hsien Tseng ◽  
Bo-Ru Chen ◽  
Yi-Ru Wu ◽  
Cheng-Liang Huang ◽  
...  
Keyword(s):  
Gold Nanoclusters ◽  
Quantum Yields ◽  
Excitation Wavelength ◽  
Aqueous Environment ◽  
Glutathione Disulfide ◽  
Ag Nps ◽  
Net Charge ◽  
Red Color ◽  
New Strategy ◽  
Capping Ligands

A new strategy using silver nanoparticles (Ag NPs) to synthesize thiolated Au NCs is demonstrated. The quasi-spherical Ag NPs serve as a platform, functioning as a reducing agent for Au (III) and attracting capping ligands to the surface of the Ag NPs. Glutathione disulfide (GSSG) and dithiothreitol (DTT) were used as capping ligands to synthesize thiolated Au NCs (glutathione-Au NCs and DTT-Au NCs). The glutathione-Au NCs and DTT-Au NCs showed red color luminance with similar emission wavelengths (630 nm) at an excitation wavelength of 354 nm. The quantum yields of the glutathione-Au NCs and DTT-Au NCs were measured to be 7.3% and 7.0%, respectively. An electrophoretic mobility assay showed that the glutathione-Au NCs moved toward the anode, while the DTT-Au NCs were not mobile under the electric field, suggesting that the total net charge of the thiolated Au NCs is determined by the charges on the capping ligands. The detection of the KSV values, 26 M−1 and 0 M−1, respectively, revealed that glutathione-Au NCs are much more accessible to an aqueous environment than DTT-Au NCs.

A New Strategy to Construct Gold Nanoclusters-Based Optical Probe Using Luminescence Resonance Energy Transfer

2021 ◽  
Author(s):  
Shuyang Zhai ◽  
Wei Hu ◽  
Chen Fan ◽  
Wenqi Feng ◽  
Zhi-hong Liu
Keyword(s):  
Energy Transfer ◽  
Gold Nanoclusters ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Optical Probe ◽  
Luminescent Materials ◽  
Metal Nanoclusters ◽  
New Strategy ◽  
Photoluminescence Efficiency

Monolayer-protected metal nanoclusters (MPCs) are emerging as intriguing luminescent materials, but the construction of MPCs-based optical probe is still scarce because of both the limited photoluminescence efficiency of MPCs and...

Improving the Fluorescence Concentration Quenching of Porphyrin Potassium Salt by Ag Nano Colloids

2016 ◽  
Vol 16 (4) ◽  
pp. 3646-3652
Author(s):  
Ailing Yang ◽  
Ning Wang ◽  
Yujin Wang ◽  
Shunpin Li ◽  
Lele Wang ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Potassium Salt ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Concentration Quenching ◽  
Excitation Wavelength ◽  
Ag Nps ◽  
Silver Colloids ◽  
Enhancing Effect ◽  
Fluorescence Enhancing

Silver nanoparticles (NPs) with diameters less than 25 nm, and 5, 10, 15, 20-tetrakis(4-carboxy-phenyl) porphyrin potassium salt (K4TCPPS) was synthesized. By adding silver colloids into the K4TCPPS solutions, the fluorescence concentration quenching of the K4TCPPS solutions was improved between 1×10−6–5×10−4 M, depending on the size of the Ag NPs, the concentration of the K4TCPPS and the excitation wavelength. Under excitation wavelengths of 360 and 414 nm, the enhancement was in the range of 0.34–22.8, and 0.71–82.46, respectively. The enhancement increased with decreasing size of the Ag NPs. At the two highest enhancements, the concentrations of the K4TCPPS solutions were 1×10−4 and 1×10−5 M respectively, and the size of the Ag NPs was about 5 nm. The main reasons for the fluorescence enhancing effect are due to fluorescence resonance energy transfer (FRET) between K4TCPPS molecules and Ag NPs, and decreased collision quenching between free K4TCPPS molecules, and free K4TCPPS molecules with Ag NPs. Our results showed that Ag NPs with sizes of about 5 nm can effectively improve the fluorescence concentration quenching of K4TCPPS solutions. This result also suggests that it is possible to use noble metal NPs to improve fluorescence concentration quenching.

Quantum Dot/Plasmonic Nanoparticle Metachromophores with Quantum Yields That Vary with Excitation Wavelength

Nano Letters ◽  
2011 ◽  
Vol 11 (7) ◽  
pp. 2725-2730 ◽  
Author(s):  
Keiko Munechika ◽  
Yeechi Chen ◽  
Andreas F. Tillack ◽  
Abhishek P. Kulkarni ◽  
Ilan Jen-La Plante ◽  
...  
Keyword(s):  
Quantum Dot ◽  
Quantum Yields ◽  
Excitation Wavelength ◽  
Plasmonic Nanoparticle

Electronically Coupled Gold Nanoclusters Render Deep-Red Emission with High Quantum Yields

2020 ◽  
Vol 11 (21) ◽  
pp. 9344-9350
Author(s):  
Hsiu-Ying Huang ◽  
Kun-Bin Ca ◽  
Chong-Cho Io ◽  
Po-Wen Chen ◽  
Ruth Jeane Soebroto ◽  
...  
Keyword(s):  
Gold Nanoclusters ◽  
Quantum Yields ◽  
Red Emission ◽  
High Quantum

Luminescence quantum yields of gold nanoparticles varying with excitation wavelengths

Nanoscale ◽  
2016 ◽  
Vol 8 (4) ◽  
pp. 2188-2194 ◽  
Author(s):  
Yuqing Cheng ◽  
Guowei Lu ◽  
Yingbo He ◽  
Hongming Shen ◽  
Jingyi Zhao ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Quantum Yields ◽  
Excitation Wavelength

The photoluminescence quantum yields of gold nanoparticles, nanorods and nanobipyramids are excitation wavelength dependent.

Understanding the Photoluminescence Mechanism of Carbon Dots

MRS Advances ◽  
2017 ◽  
Vol 2 (51) ◽  
pp. 2927-2934 ◽  
Author(s):  
Zhoufeng Jiang ◽  
Marta J. Krysmann ◽  
Antonios Kelarakis ◽  
Petr Koutnik ◽  
Pavel Anzenbacher ◽  
...  
Keyword(s):  
Carbon Dots ◽  
Quantum Yields ◽  
Excitation Wavelength ◽  
Time Resolved ◽  
Light Emitting ◽  
Dependent Component ◽  
Different Types ◽  
Photoluminescence Mechanism ◽  
Time Resolved Photoluminescence ◽  
Absolute Quantum

ABSTRACTThe carbon dots were investigated to reveal their light-emitting mechanism. The fluorescence spectra of carbon dots show typically two different types of photoluminescence: the excitation-independent component in the short wavelength, and the excitation-dependent component in the longer wavelength. The UV-Vis spectrum of carbon dots shows the absorption maximum of 340 nm which should be accredited to the n-π* transition of the carbonyl group in carbon dots. Absolute quantum yields of carbon dots dispersed in Polyvinyl alcohol is around 15% when the excitation wavelength is less than 425 nm, but decreases continuously when the excitation wavelength increases. The decay lifetimes of the carbon dots also show an abrupt change at excitation wavelength 425 nm. Time resolved photoluminescence was implemented from 31K to 291K to study the photoluminescence decay dynamics of carbon dots, resulting in the continuously decreasing of the lifetime as the temperature increases.

High-Quality Water-Soluble Core/Shell/Shell CdSe/CdS/ZnS Quantum Dots Balanced by Ionic and Nonionic Hydrophilic Capping Ligands

NANO ◽  
2016 ◽  
Vol 11 (07) ◽  
pp. 1650073 ◽  
Author(s):  
Lu Liu ◽  
Hu Xu ◽  
Bing Shen ◽  
Xinhua Zhong
Keyword(s):  
Quantum Dots ◽  
Colloidal Stability ◽  
Water Soluble ◽  
Quantum Yields ◽  
Surface Charges ◽  
Fluorescence Quantum Yields ◽  
Carboxylic Groups ◽  
Potential Applications ◽  
High Fluorescence ◽  
Capping Ligands

Pentaerythritol tetrakis 3-mercaptopropionate (PTMP) grafted poly(acryl acid) (PAA) ionic hydrophilic oligomer PAA-PTMP (PP) and dihydrolipoic acid (DHLA) grafted methoxypoly(ethylene glycol) (mPEG) nonionic hydrophilic oligomer mPEG-DHLA (PD) have been designed, synthesized and used as co-capping ligands in water-solubilization of hydrophobic quantum dots (QDs) via ligand exchange. The obtained oligomers with multi-thiol groups could bind strongly to the surface atoms of QDs. Meanwhile, the carboxyl groups (from PP) and mPEG segment (from PD) can render QDs water-soluble, and the free carboxylic groups can possibly be used for the further bioconjugation. The resulting water-soluble QDs have been characterized by ultraviolet-visible (UV-Vis), fluorescence, Fourier transform infrared (FTIR) spectroscopy as well as transmission electron microscopy (TEM) and dynamic light scattering (DLS) techniques. The water-soluble QDs have relatively small hydrodynamic size (10[Formula: see text]12 nm), and importantly, retain high fluorescence quantum yields (up to 45%) compared with that of the originally hydrophobic QDs (49%). In addition, they have tunable surface charges and show excellent colloidal stability over a relatively broad pH range ([Formula: see text]), in high salt concentration, and even after thermal treatment at 100[Formula: see text]C. These results indicate that the water-soluble QDs coated by PP and PD oligomers have potential applications in cellular imaging and biosensor.

scholarly journals Synthesis of Dy3+, Eu3+ and Tb3+ Activated Y2O2S Optoelectronic Phosphors for N-UV LED Applications

2020 ◽  
Vol 9 (4) ◽  
pp. 2068-2074
Keyword(s):  
Solid State Reaction Method ◽  
Yellow Emission ◽  
Strong Line ◽  
Excitation Wavelength ◽  
Excitation Spectra ◽  
Near Ultraviolet ◽  
Red Color ◽  
Blue Radiation ◽  
Bright Color ◽  
Color Emission

In this, a series of iso-structural Y2O2S (RE3+ = Dy3+ , Eu3+ and Tb3+) phosphors were synthesized by high temperature solid state reaction method. All the phosphors exhibit strong line and broad excitation in the near ultraviolet (n-UV) region. Bright color emission in blue, green and red color region of electromagnetic hue cycle was noticed. The concentration of activator doped was optimized from the photoluminescence (PL) study. The quenching in luminescence intensity after particular concentration of dopant is discussed here. Y2O2S phosphor doped with Dy3+displays useful blue and yellow emission bands at 487nm and 574nm, when stimulated by 388nm excitation wavelength. Y2O2S:Eu3+ phosphor displays an orange and red emission at 594nm and 620nm, when stimulated at 396 nm. Whereas, Y2O2S:Tb3+ phosphor displays weak blue radiation in the range 485nm and strong green radiation at 545nm, when stimulated at 305 nm. The excitation spectra used for the Y2O2S:RE3+ (RE3+ = Dy3+ , Eu3+ and Tb3+) phosphor is in the near ultraviolet (n-UV) region spanning from 300 nm to 400 nm, which is a peculiarity of near ultraviolet stimulated LED. The outcome of the RE3+ (RE3+= Dy3+ , Eu3+and Tb3+) absorption on the luminescence properties of Y2O2S:RE3+ phosphors was also studied.

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