Article

SERS not to be taken for granted in the presence of oxygen

Department of Chemistry, Chemical Biology and Biomedical Engineering, Stevens Institute of Technology, Castle Point on Hudson, Hoboken, New Jersey 07030, USA.
Journal of the American Chemical Society (Impact Factor: 11.44). 06/2009; 131:7480-7481. DOI: 10.1021/ja807458x

ABSTRACT Cited By (since 1996): 14

0 Bookmarks
 · 
78 Views
  • [Show abstract] [Hide abstract]
    ABSTRACT: In this work, gold nanostars (AuNSs) with size around 90 nm were prepared through an easy one-step method. They show excellent catalytic activity and large surface-enhanced Raman scattering (SERS) activity at the same time. Surprisingly, they exhibited different catalytic performance on the reduction of aromatic nitro compounds with different substituents on the para position. To understand such a difference, the SERS spectra were recorded, showing that the molecular orientation of reactants on the gold surface were different. We anticipate that this research will help to understand the relationship of the molecular orientation with the catalytic activity of gold nanoparticles.
    Colloids and Surfaces A Physicochemical and Engineering Aspects 10/2014; · 2.35 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: As a bio/chemical sensing technique, surface enhanced Raman spectroscopy (SERS) offers sensitivity comparable to that of fluorescence detection while providing highly specific information about the analyte. Although single molecule identification with SERS was demonstrated over a decade ago, today a need exists to develop practical solutions for point-of-sample and point-of-care SERS systems. In recent years, optofluidic SERS has emerged, in which microfluidic functions are integrated to improve the performance of SERS. Advancements in optofluidic SERS are leading towards portable analytical systems, but the devices are currently too expensive and too cumbersome for limited resource settings. Recently, we demonstrated the fabrication of SERS substrates by inkjet printing silver nanostructures onto paper. Using a low-cost commercial inkjet printer, we chemically patterned cellulose paper to form hydrophobic regions, which can control the aqueous sample on the paper microsystem. Additionally, we inkjet-printed silver nanoparticles with micro-scale precision to form SERS-active biosensors. Using these devices, we have been able to achieve detection limits comparable to conventional nanofabricated substrates. Furthermore, we leverage the fluidic properties to enhance the performance of the SERS devices while also enabling unprecedented ease of use. Paper dipsticks concentrate a relatively large sample volume into a small SERS-active detection region at the tip. Likewise, paper swabs collect samples from a large surface area and concentrate the collected molecules into a SERS sensor on the paper. We will summarize the progress in the fabrication and use of these paper-based optofluidic devices, and will describe their use in practical applications for point-of-sample detection.
    Proc SPIE 02/2012;
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The front transparent conductive oxide layer is a source of significant optical and electrical losses in silicon heterojunction solar cells because of the trade-off between free-carrier absorption and sheet resistance. We demonstrate that hydrogen-doped indium oxide (IO:H), which has an electron mobility of over 100 cm2/V s, reduces these losses compared to traditional, low-mobility transparent conductive oxides, but suffers from high contact resistance at the interface of the IO:H layer and the silver front electrode grid. This problem is avoided by inserting a thin indium tin oxide (ITO) layer at the IO:H/silver interface. Such IO:H/ITO bilayers have low contact resistance, sheet resistance, and free-carrier absorption, and outperform IO:H-only or ITO-only layers in solar cells. We report a certified efficiency of 22.1% for a 4-cm2 screen-printed silicon heterojunction solar cell employing an IO:H/ITO bilayer as the front transparent conductive oxide.
    Solar Energy Materials and Solar Cells 08/2013; 115:151–156. · 5.03 Impact Factor