scholarly journals Amorphous Carbon Generation as a Photocatalytic Reaction on DNA-Assembled Gold and Silver Nanostructures

Molecules ◽  
2019 ◽  
Vol 24 (12) ◽  
pp. 2324 ◽  
Author(s):  
Christian Heck ◽  
Yuya Kanehira ◽  
Janina Kneipp ◽  
Ilko Bald

Background signals from in situ-formed amorphous carbon, despite not being fully understood, are known to be a common issue in few-molecule surface-enhanced Raman scattering (SERS). Here, discrete gold and silver nanoparticle aggregates assembled by DNA origami were used to study the conditions for the formation of amorphous carbon during SERS measurements. Gold and silver dimers were exposed to laser light of varied power densities and wavelengths. Amorphous carbon prevalently formed on silver aggregates and at high power densities. Time-resolved measurements enabled us to follow the formation of amorphous carbon. Silver nanolenses consisting of three differently-sized silver nanoparticles were used to follow the generation of amorphous carbon at the single-nanostructure level. This allowed observation of the many sharp peaks that constitute the broad amorphous carbon signal found in ensemble measurements. In conclusion, we highlight strategies to prevent amorphous carbon formation, especially for DNA-assembled SERS substrates.

Nanoscale ◽  
2018 ◽  
Vol 10 (8) ◽  
pp. 3680-3687 ◽  
Author(s):  
Taeksu Lee ◽  
Jung-Sub Wi ◽  
Aram Oh ◽  
Hee-Kyung Na ◽  
JaeJong Lee ◽  
...  

Highly sensitive and reproducible suface enhanced Raman spectroscopy (SERS) substrates were fabricated by growing multiple silver nanocrystals inside periodically arrayed gold nanobowls.


2017 ◽  
Vol 68 (1) ◽  
pp. 98 ◽  
Author(s):  
Alok Kumar Srivastava ◽  
Punam Awasthi ◽  
Sanjay Kanojia ◽  
N. S. Neeraj ◽  
Pankaj Sharma ◽  
...  

<p class="p1">A comparison of Surface Enhanced Raman Scattering (SERS) activity of chemically synthesised silver nanostructures with different shapes is reported. The silver nanostructures of cubical, prism and wire like morphology were synthesised using chemical synthesis route and utilised as SERS substrates. The sensors were fabricated by spin coating these materials over a Silicon or glass substrate. The fabricated sensors were used to analyse response with two different analytes, 4-Mercaptobenzoic acid and Rhodamine 6G under different concentrations. The signal enhancement was compared with a silver coated thin film over glass substrate and it was observed that the enhancement of the order of 10<span class="s1"><sup>3 </sup></span>is achieved. The nanowire performed better than the other forms of silver and gave a higher signal enhancement for all the analytes as compared to other nanostructures. The fabricated sensors may be useful for various applications including explosive and biowarfare agent detection.</p>


2016 ◽  
Vol 18 (14) ◽  
pp. 9405-9411 ◽  
Author(s):  
C. Awada ◽  
J. Plathier ◽  
C. Dab ◽  
F. Charra ◽  
L. Douillard ◽  
...  

The need for a dedicated spectroscopic technique with nanoscale resolution to characterize SERS substrates pushed us to develop a proof of concept of a functionalized tip–surface enhanced Raman scattering (FTERS) technique.


2016 ◽  
Vol 18 (1-2) ◽  
Author(s):  
Mohammad Salehi ◽  
Angela Hamann-Steinmeier

AbstractSurface-enhanced Raman scattering (SERS) is a vibrational spectroscopy technique, which is used in the areas of medical diagnostics. This technique use the advantages of biofunctionalized nanoparticles (NPs) for imaging and quantifying of target molecules such as proteins in assays, cells and tissues. The lack of reliability and reproducibility of the results are major challenges in the application of diagnostics based of SERS substrates. The biofunction and success of nanomedical tasks depends on the quality of each involved element like antibodies (IgGs) and nanostructures before, during and after preparation or conjunction with nanoparticles. This short review summarizes current designs of different SERS substrates and highlights the improvement of particularly simple and gentle conjugation methods for targeting research with SERS labels.


Nanomaterials ◽  
2018 ◽  
Vol 8 (7) ◽  
pp. 520 ◽  
Author(s):  
Jia Zhu ◽  
Guanzhou Lin ◽  
Meizhang Wu ◽  
Zhuojie Chen ◽  
Peimin Lu ◽  
...  

Technology transfer from laboratory into practical application needs to meet the demands of economic viability and operational simplicity. This paper reports a simple and convenient strategy to fabricate large-scale and ultrasensitive surface-enhanced Raman scattering (SERS) substrates. In this strategy, no toxic chemicals or sophisticated instruments are required to fabricate the SERS substrates. On one hand, Ag nanoparticles (NPs) with relatively uniform size were synthesized using the modified Tollens method, which employs an ultra-low concentration of Ag+ and excessive amounts of glucose as a reducing agent. On the other hand, when a drop of the colloidal Ag NPs dries on a horizontal solid surface, the droplet becomes ropy, turns into a layered structure under gravity, and hardens. During evaporation, capillary flow was burdened by viscidity resistance from the ropy glucose solution. Thus, the coffee-ring effect is eliminated, leading to a uniform deposition of Ag NPs. With this method, flat Ag NPs-based SERS active films were formed in array-well plates defined by hole-shaped polydimethylsiloxane (PDMS) structures bonded on glass substrates, which were made for convenient detection. The strong SERS activity of these substrates allowed us to reach detection limits down to 10−14 M of Rhodamine 6 G and 10−10 M of thiram (pesticide).


2010 ◽  
Vol 100 (1) ◽  
pp. 83-88 ◽  
Author(s):  
W. C. Zhang ◽  
X. L. Wu ◽  
C. X. Kan ◽  
F. M. Pan ◽  
H. T. Chen ◽  
...  

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