In Situ Determination of Colloidal Gold Concentrations with UV–Vis Spectroscopy: Limitations and Perspectives

Hendel, Thomas; Wuithschick, Maria; Kettemann, Frieder; Birnbaum, Alexander; Rademann, Klaus; Polte, Jörg

doi:10.1021/ac502053s

Cited by 181 publications

(188 citation statements)

References 99 publications

(227 reference statements)

Supporting

Mentioning

163

Contrasting

Unclassified

Order By: Relevance

“…The AuNP extinction at wavelength below ≈450 nm are mostly caused by interband transitions. [ 21 ] This Au-related absorption is superimposed by the absorption of the semiconductor CdS.…”

Section: Growth Of Cadmium Sulfi De On Gold Nanoparticlesmentioning

confidence: 99%

Chloride Ion Mediated Synthesis of Metal/Semiconductor Hybrid Nanocrystals

Hinrichs

Galchenko

Kodanek

et al. 2016

Small

View full text Add to dashboard Cite

A synthetic route to prepare metal-semiconductor hybrid nanoparticles is presented, along with the possibility to tune the ratio of primary to secondary nucleation and the morphology of the semiconductor material grown on the metal nanoparticle seeds. Gold and cobalt-platinum nanoparticles are employed as metal seeds, on which CdS or CdSe is grown. Using transmission electron microscopy, absorption spectroscopy (UV-vis), and powder X-ray diffraction as characterization techniques, a significant influence of chloride ions on the type of nucleation (that is, secondary or primary nucleation) as well as on the shape of the resulting heterostructures is observed. Partially replacing the commonly used cadmium precursor CdO by varying amounts of CdCl2 opens access to rod-like, multiarmed, flower-like, and bullet-like structures. The results suggest that neither pure CdO nor pure CdCl2 as precursors but only a mixture of both make these structures obtainable. In this article, the influence of the chloride ion concentration during semiconductor growth on metal seeds is investigated in depth. The morphology of the resulting heterostructures is characterized carefully, and a growth mechanism is suggested. Furthermore, it is shown that this synthetic approach can be transferred to seeds of various metals such as platinum, gold, and cobalt platinum.

show abstract

“…The AuNP extinction at wavelength below ≈450 nm are mostly caused by interband transitions. [ 21 ] This Au-related absorption is superimposed by the absorption of the semiconductor CdS.…”

Section: Growth Of Cadmium Sulfi De On Gold Nanoparticlesmentioning

confidence: 99%

Chloride Ion Mediated Synthesis of Metal/Semiconductor Hybrid Nanocrystals

Hinrichs

Galchenko

Kodanek

et al. 2016

Small

View full text Add to dashboard Cite

show abstract

“…Charging effects are known to influence the optical properties of AuNP significantly. 15,33 Aggregates which were observed in TEM images of samples taken during early stages of the synthesis are most likely artefacts formed during the sample preparation process (drying) and do not represent the actual properties of the colloidal solution. A detailed discussion on the existence or non-existence of aggregates can be found in SI-2.…”

Section: Figurementioning

confidence: 99%

Turkevich in New Robes: Key Questions Answered for the Most Common Gold Nanoparticle Synthesis

et al. 2015

Self Cite

View full text Add to dashboard Cite

This contribution provides a comprehensive mechanistic picture of the gold nanoparticle synthesis by citrate reduction of HAuCl4, known as Turkevich method, by addressing five key questions. The synthesis leads to monodisperse final particles as a result of a seed-mediated growth mechanism. In the initial phase of the synthesis, seed particles are formed onto which the residual gold is distributed during the course of reaction. It is shown that this mechanism is a fortunate coincidence created by a favorable interplay of several chemical and physicochemical processes which initiate but also terminate the formation of seed particles and prevent the formation of further particles at later stages of reaction. Since no further particles are formed after seed particle formation, the number of seeds defines the final total particle number and therefore the final size. The gained understanding allows illustrating the influence of reaction conditions on the growth process and thus the final size distribution.

show abstract

“…Figure 1A plots the normalized absorbance values (at 400 nm wavelength) of the different nanostructures. The absorbance value at 400 nm has typically been correlated with the gold atom [Au] concentration in the colloid . Thus, the normalization (in Figure 1A and others) allow for a direct comparison of the plasmonic behavior (a functional parameter) of different nanomorphologies for identical gold concentration (a physical parameter) present in each colloid.…”

Section: Resultsmentioning

confidence: 99%

Plasmonic Nanoassemblies: Tentacles Beat Satellites for Boosting Broadband NIR Plasmon Coupling Providing a Novel Candidate for SERS and Photothermal Therapy

Dey

Tabish

Mosca

et al. 2020

Small

View full text Add to dashboard Cite

Optical theranostic applications demand near‐infrared (NIR) localized surface plasmon resonance (LSPR) and maximized electric field at nanosurfaces and nanojunctions, aiding diagnosis via Raman or optoacoustic imaging, and photothermal‐based therapies. To this end, multiple permutations and combinations of plasmonic nanostructures and molecular “glues” or linkers are employed to obtain nanoassemblies, such as nanobranches and core–satellite morphologies. An advanced nanoassembly morphology comprising multiple linear tentacles anchored onto a spherical core is reported here. Importantly, this core‐multi‐tentacle‐nanoassembly (CMT) benefits from numerous plasmonic interactions between multiple 5 nm gold nanoparticles (NPs) forming each tentacle as well as tentacle to core (15 nm) coupling. This results in an intense LSPR across the “biological optical window” of 650−1100 nm. It is shown that the combined interactions are responsible for the broadband LSPR and the intense electric field, otherwise not achievable with core–satellite morphologies. Further the sub 80 nm CMTs boosted NIR‐surface‐enhanced Raman scattering (SERS), with detection of SERS labels at 47 × 10‐9 m, as well as lower toxicity to noncancerous cell lines (human fibroblast Wi38) than observed for cancerous cell lines (human breast cancer MCF7), presents itself as an attractive candidate for use as biomedical theranostics agents.

show abstract

In Situ Determination of Colloidal Gold Concentrations with UV–Vis Spectroscopy: Limitations and Perspectives

Cited by 181 publications

References 99 publications

Chloride Ion Mediated Synthesis of Metal/Semiconductor Hybrid Nanocrystals

Chloride Ion Mediated Synthesis of Metal/Semiconductor Hybrid Nanocrystals

Turkevich in New Robes: Key Questions Answered for the Most Common Gold Nanoparticle Synthesis

Plasmonic Nanoassemblies: Tentacles Beat Satellites for Boosting Broadband NIR Plasmon Coupling Providing a Novel Candidate for SERS and Photothermal Therapy

Contact Info

Product

Resources

About