A Raman and SERS study on the interactions of aza[5]helicene and aza[6]helicene with a nanostructured gold surface

2020 ◽  
Vol 111 ◽  
pp. 103180
Author(s):  
Chiara Zanchi ◽  
Andrea Lucotti ◽  
Matteo Pistaffa ◽  
Paolo M. Ossi ◽  
Sebastiano Trusso ◽  
...  
2015 ◽  
Vol 87 (5) ◽  
pp. 2588-2592 ◽  
Author(s):  
Tao Yuan ◽  
Loan Le Thi Ngoc ◽  
Jan van Nieuwkasteele ◽  
Mathieu Odijk ◽  
Albert van den Berg ◽  
...  

2011 ◽  
Vol 2 ◽  
pp. 501-508 ◽  
Author(s):  
Dana Cialla ◽  
Karina Weber ◽  
René Böhme ◽  
Uwe Hübner ◽  
Henrik Schneidewind ◽  
...  

In order to combine the advantages of fluorescence and surface-enhanced Raman spectroscopy (SERS) on the same chip platform, a nanostructured gold surface with a unique design, allowing both the sensitive detection of fluorescence light together with the specific Raman fingerprint of the fluorescent molecules, was established. This task requires the fabrication of plasmonic arrays that permit the binding of molecules of interest at different distances from the metallic surface. The most efficient SERS enhancement is achieved for molecules directly adsorbed on the metallic surface due to the strong field enhancement, but where, however, the fluorescence is quenched most efficiently. Furthermore, the fluorescence can be enhanced efficiently by careful adjustment of the optical behavior of the plasmonic arrays. In this article, the simultaneous application of SERS and fluorescence, through the use of various gold nanostructured arrays, is demonstrated by the realization of a DNA detection scheme. The results shown open the way to more flexible use of plasmonic arrays in bioanalytics.


Plasmonics ◽  
2018 ◽  
Vol 13 (6) ◽  
pp. 2117-2124 ◽  
Author(s):  
N. R. Agarwal ◽  
M. Tommasini ◽  
E. Ciusani ◽  
A. Lucotti ◽  
S. Trusso ◽  
...  

2010 ◽  
Vol 28 (1) ◽  
pp. 184-188
Author(s):  
Jeongjin Lee ◽  
Junsu Park ◽  
Byoung Kyu Kwak ◽  
Inhee Choi ◽  
Younghun Kim ◽  
...  

Molecules ◽  
2021 ◽  
Vol 26 (17) ◽  
pp. 5422
Author(s):  
Nguyen Thi Nhat Hang ◽  
Nguyen Thanh Si ◽  
Minh Tho Nguyen ◽  
Pham Vu Nhat

Computational approaches are employed to elucidate the binding mechanism and the SERS phenomenon of 6-mercaptopurine (6MP) adsorbed on the tetrahedral Au20 cluster as a simple model for a nanostructured gold surface. Computations are carried out in both vacuum and aqueous environments using a continuum model. In the gaseous phase and neutral conditions, interaction of 6MP with the gold cluster is mostly dominated by a covalent Au−S bond and partially stabilized by the Au⋅⋅⋅H−N coupling. However, in acidic solution, the nonconventional Au⋅⋅⋅H−S hydrogen-bond becomes the most favorable binding mode. The 6MP affinity for gold clusters decreases in the order of vacuum > neutral solution > acidic medium. During the adsorption, the energy gap of Au20 substantially declines, leading to an increase in its electrical conductivity, which can be converted to an electrical noise. Moreover, such interaction is likely a reversible process and triggered by either the low pH in sick tissues or the presence of cysteine residues in protein matrices. While N−H bending and stretching vibrations play major roles in the SERS phenomenon of 6MP on gold surfaces in neutral solution, the strongest enhancement in acidic environment is mostly due to an Au⋅⋅⋅H−S coupling, rather than an aromatic ring-gold surface π overlap as previously proposed.


2011 ◽  
Vol 1351 ◽  
Author(s):  
László Guczi ◽  
Andrea Beck ◽  
Tímea Benkó ◽  
Zoltán Pászti

ABSTRACTBased on results taken from our own experience and the general literature, in the present contribution issues related to the importance of the particle size and morphology in gold catalysis are considered. Although in reactions of small molecules like carbon monoxide nanosized or otherwise nanostructured gold surfaces are the most active catalysts, especially if forming interface with certain oxides, it turns out that in some cases - independently of the interface - the key issue is the available size of extended gold surface dictating the reaction rate. This dilemma is explored in the paper.


2012 ◽  
Vol 82 ◽  
pp. 202-204 ◽  
Author(s):  
Shili Xu ◽  
Yuan Yao ◽  
Zelin Li ◽  
Hefang Zhang ◽  
Fuli Huang ◽  
...  

Author(s):  
Norman J. Armendariz ◽  
Prawin Paulraj

Abstract The European Union is banning the use of Pb in electronic products starting July 1st, 2006. Printed circuit board assemblies or “motherboards” require that planned CPU sockets and BGA chipsets use lead-free solder ball compositions at the second level interconnections (SLI) to attach to a printed circuit board (PCB) and survive various assembly and reliability test conditions for end-use deployment. Intel is pro-actively preparing for this anticipated Pb ban, by evaluating a new lead free (LF) solder alloy in the ternary Tin- Silver-Copper (Sn4.0Ag0.5Cu) system and developing higher temperature board assembly processes. This will be pursued with a focus on achieving the lowest process temperature required to avoid deleterious higher temperature effects and still achieve a metallurgically compatible solder joint. One primary factor is the elevated peak reflow temperature required for surface mount technology (SMT) LF assembly, which is approximately 250 °C compared to present eutectic tin/lead (Sn37Pb) reflow temperatures of around 220 °C. In addition, extended SMT time-above-liquidus (TAL) and subsequent cooling rates are also a concern not only for the critical BGA chipsets and CPU BGA sockets but to other components similarly attached to the same PCB substrate. PCBs used were conventional FR-4 substrates with organic solder preservative on the copper pads and mechanical daisychanged FCBGA components with direct immersion gold surface finish on their copper pads. However, a materials analysis method and approach is also required to characterize and evaluate the effect of low peak temperature LF SMT processing on the PBA SLI to identify the absolute limits or “cliffs” and determine if the minimum processing temperature and TAL could be further lowered. The SLI system is characterized using various microanalytical techniques, such as, conventional optical microscopy, scanning electron microscopy, energy dispersive spectroscopy and microhardness testing. In addition, the SLI is further characterized using macroanalytical techniques such as dye penetrant testing (DPT) with controlled tensile testing for mechanical strength in addition to disbond and crack area mapping to complete the analysis.


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