Post-Synthesis Modification of Photoluminescent and Electrochemiluminescent Au Nanoclusters with Dopamine

Here, we report a post-synthesis functionalization of the shell of Au nanoclusters (NCs) synthesized using glutathione as a thiolate ligand. The as-synthesized Au NCs are subjected to the post-synthesis functionalization via amidic coupling of dopamine on the cluster shell to tailor photoluminescence (PL) and electrochemiluminescence (ECL) features of the Au NCs. Because the NCs’ PL at ca. 610 nm is primarily ascribed to the Au(I)-thiolate (SG) motifs on the cluster shell of the NCs, the post-synthesis functionalization of the cluster shell enhanced the PL intensity of the Au NCs via rigidification of the cluster shell. In contrast to the PL enhancement, the post-synthesis modification of the cluster shell does not enhance the near-infrared (NIR) ECL of the NCs because the NIR ECL at ca. 800 nm is ascribed to the Au(0)-SG motifs in the metallic core of the NCs.

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Near-Infrared Electrochemiluminescence of Dual-Stabilizer-Capped Au Nanoclusters for Immunoassays

ACS Applied Nano Materials ◽

10.1021/acsanm.0c03284 ◽

2021 ◽

Author(s):

Hongying Jia ◽

Siqi Yu ◽

Lei Yang ◽

Qin Wei ◽

Huangxian Ju

Keyword(s):

Near Infrared ◽

Au Nanoclusters

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Metal ions-modulated near-infrared electrochemiluminescence from Au nanoclusters enhanced by 4-(2-Hydroxyethyl)-1-piperazineethanesulfonic acid at physiological pH

Electrochimica Acta ◽

10.1016/j.electacta.2018.06.067 ◽

2018 ◽

Vol 282 ◽

pp. 369-376 ◽

Cited By ~ 6

Author(s):

Tanyu Wang ◽

Hedi Ma ◽

Jonathan W. Padelford ◽

Edgardo Lobo ◽

Minh Tri Tran ◽

...

Keyword(s):

Metal Ions ◽

Near Infrared ◽

Au Nanoclusters ◽

Piperazineethanesulfonic Acid

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Single-Step Photochemical Formation of Near-Infrared-Absorbing Gold Nanomosaic within PNIPAm Microgels: Candidates for Photothermal Drug Delivery

Nanomaterials ◽

10.3390/nano10071251 ◽

2020 ◽

Vol 10 (7) ◽

pp. 1251

Author(s):

Sreekar B. Marpu ◽

Brian Leon Kamras ◽

Nooshin MirzaNasiri ◽

Oussama Elbjeirami ◽

Denise Perry Simmons ◽

...

Keyword(s):

Near Infrared ◽

Dimethyl Sulfide ◽

Test Sample ◽

Single Step ◽

Step Method ◽

Photochemical Reduction ◽

Order Of Magnitude ◽

Post Synthesis ◽

Lamp Source ◽

Hybrid Microgels

This work demonstrates the dynamic potential for tailoring the surface plasmon resonance (SPR), size, and shapes of gold nanoparticles (AuNPs) starting from an Au(I) precursor, chloro(dimethyl sulfide)gold (I) (Au(Me2S)Cl), in lieu of the conventional Au(III) precursor hydrogen tetrachloroaurate (III) hydrate (HAuCl4). Our approach presents a one-step method that permits regulation of an Au(I) precursor to form either visible-absorbing gold nanospheres or near-infrared-window (NIRW)-absorbing anisotropic AuNPs. A collection of shapes is obtained for the NIR-absorbing AuNPs herein, giving rise to spontaneously formed nanomosaic (NIR-absorbing anisotropic gold nanomosaic, NIRAuNM) without a dominant geometry for the tesserae elements that comprise the mosaic. Nonetheless, NIRAuNM exhibited high stability; one test sample remains stable with the same SPR absorption profile 7 years post-synthesis thus far. These NIRAuNM are generated within thermoresponsive poly(N-isopropylacrylamide) (PNIPAm) microgels, without the addition of any growth-assisting surfactants or reducing agents. Our directed-selection methodology is based on the photochemical reduction of a light-, heat-, and water-sensitive Au(I) precursor via a disproportionation mechanism. The NIRAuNM stabilized within the thermoresponsive microgels demonstrates a light-activated size decrease of the microgels. On irradiation with a NIR lamp source, the percent decrease in the size of the microgels loaded with NIRAuNM is at least five times greater compared to the control microgels. The concept of photothermal shrinkage of hybrid microgels is further demonstrated by the release of a model luminescent dye, as a drug release model. The absorbance and emission of the model dye released from the hybrid microgels are over an order of magnitude higher compared to the absorbance and emission of the dye released from the unloaded-control microgels.

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One-pot synthesis of β-cyclodextrin modified Au nanoclusters with near-infrared emission

Chemical Communications ◽

10.1039/d0cc00713g ◽

2020 ◽

Vol 56 (42) ◽

pp. 5580-5583 ◽

Cited By ~ 5

Author(s):

Wenjing Li ◽

Xi Wang ◽

Tao Jiang ◽

Xiang Ma ◽

He Tian

Keyword(s):

Near Infrared ◽

Gold Nanoclusters ◽

Infrared Emission ◽

Au Nanoclusters ◽

One Pot ◽

One Pot Synthesis ◽

Near Infrared Emission

β-Cyclodextrin modified gold nanoclusters with near-infrared emission were facilely and successfully prepared based on a one-pot and green supramolecular macrocycle modification strategy.

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Effects of Nitrogen Impurity Concentration on Nitrogen-Vacancy Center Formation in 4H-SiC

Materials Science Forum ◽

10.4028/www.scientific.net/msf.1004.349 ◽

2020 ◽

Vol 1004 ◽

pp. 349-354

Author(s):

Takuma Narahara ◽

Shin Ichiro Sato ◽

Kazutoshi Kojima ◽

Yuichi Yamazaki ◽

Yasuto Hijikata ◽

...

Keyword(s):

Near Infrared ◽

Ion Irradiation ◽

Vacancy Concentration ◽

Heavy Ion ◽

Nitrogen Vacancy ◽

N Concentration ◽

Nitrogen Concentrations ◽

Scattering Spectra ◽

Pl Intensity ◽

Raman Scattering Spectra

Spin defects of which states can be manipulated in Silicon Carbide (SiC) have drawn considerable attention because of their applications to quantum technologies. The single negatively-charged pairs of VSi and nitrogen atom (N) on an adjacent C site (NCVSi- center) in SiC is suitable for them. This paper reports the formation of NCVSi- centers on 4H-SiC epilayers with different nitrogen concentrations using light/heavy ion irradiation and subsequent thermal annealing. The formation of NCVSi- centers is characterized by the near infrared photoluminescence (PL) spectroscopy. It is shown that the PL intensity from NCVSi- centers depends on the N concentration and the ion irradiation conditions. The PL intensity increases monotonically with increasing the N concentration when the N concentration is above 2.6×1016 cm-3, whereas no linear correlation between them does not appear below that N concentration. Although the PL intensity increases with increasing defects induced by ion irradiation, the PL quenching due to neighboring residual defects appear at above the areal vacancy concentration of 1017 vac/cm2 and the broad Raman scattering spectra originated from vibration modes of amorphized regions hinder the PL from NCVSi- centers at above 1018 vac/cm2. The formation mechanism and the charge state stability of NCVSi- centers are discussed based on the obtained results.

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Near-Infrared Electrogenerated Chemiluminescence from Aqueous Soluble Lipoic Acid Au Nanoclusters

Journal of the American Chemical Society ◽

10.1021/jacs.6b03037 ◽

2016 ◽

Vol 138 (20) ◽

pp. 6380-6383 ◽

Cited By ~ 96

Author(s):

Tanyu Wang ◽

Dengchao Wang ◽

Jonathan W. Padelford ◽

Jie Jiang ◽

Gangli Wang

Keyword(s):

Lipoic Acid ◽

Near Infrared ◽

Electrogenerated Chemiluminescence ◽

Au Nanoclusters

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Defect Related Emission in Calcium Hydroxide: The Controversial Band at 780 cm−1

Crystals ◽

10.3390/cryst10040266 ◽

2020 ◽

Vol 10 (4) ◽

pp. 266 ◽

Cited By ~ 1

Author(s):

Francesca Assunta Pisu ◽

Daniele Chiriu ◽

Pier Carlo Ricci ◽

Carlo Maria Carbonaro

Keyword(s):

Cultural Heritage ◽

Calcium Hydroxide ◽

Raman Spectra ◽

Near Infrared ◽

Specific Treatment ◽

Emission Spectra ◽

Infrared Region ◽

Carbonation Process ◽

Composite Band ◽

Post Synthesis

Calcium hydroxide, a crystal involved in the cycle of calcination and carbonation of calcium oxide, finds several applications from cultural heritage to the dentistry branch or to the construction industry. When excited at 1064 nm, Raman spectra of calcium hydroxide show a broad composite band peaked at about 780 cm−1, corresponding to 1170 nm. Since it is not observed with visible excitation, the origin of this band is debated, being assigned to some pre-existent luminescent impurities or some structural defect of the lime formed after the synthesis of the material. To shed light on the formation of this band, we synthetised the lime paste starting from pure calcite powders. The obtained fresh Ca(OH)2 samples did not show any band in the investigated range, irrespective of the laser excitation applied. A detailed analysis of the excitation and emission spectra in the near infrared region did not show the 1170 nm band, supporting the hypothesis of a post-synthesis origin. Thus, we carried out thermal treatments at different temperatures (90–500 °C) and under different environments (in air or under nitrogen flux) on synthesised fresh Ca(OH)2 powders. We also investigated the time evolution of the samples, monitoring the Raman spectra over 90 days after a specific treatment. The collected data support the hypothesis of a defect-related luminescence centre, whose formation depends on the temperature and environment of the treatment, which appears as a preferential site for the carbonation process of the calcium hydroxide. These results can be useful in the field of Cultural Heritage for dating purposes, and to determine the conservation state of Ca(OH)2 containing relics to prevent the possible activation of degradation processes.

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