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Electride-Mediated Surface-Enhanced Raman Spectroscopy

A textured ceramic electride substrate that supports surface-enhanced Raman spectroscopy (SERS)
Surface plasmon-polaritons mediate conventional SERS, which exploits the enhanced electric fields that result primarily from a surface plasmon resonance condition of special metallic nanostructures. JPL has discovered a novel SERS method that is mediated by surface electride-polaritons or electrideons. The distinction between conventional SERS and electrideon-mediated SERS is based on the difference in the electronic structure of electrides and metals: in electrides, the electrons serve as anions. Electrons occupying anionic sites have unusual properties because their mass is small compared to that of typical anions. Since electrideon-mediated SERS uses electrides as the enhancing substrate, spectra from electrideon-mediated SERS of reference analytes can be used to study those unusual chemical, optical, magnetic, and electrical properties; these have applications in electroactive materials and photonics. Electride-mediated SERS has been demonstrated with a mayenite-derived ceramic compound that is thermally stable and relatively unreactive. Trans-1,2-Bis(4-pyridyl)ethylene (BPE) was used as the analyte because it has been used previously to quantitatively compare SERS-enhancing substrates. The results show that the electrides SERS enhancement factor is bounded to be greater than 104 at 532 nm excitation and greater than 103 at 785 nm excitation.
Abstract: 
NASA's Jet Propulsion Laboratory has developed a textured ceramic electride that strongly enhances the Raman scattering of organic substances (analytes) for sensitive chemical analysis. While surface-enhanced Raman spectroscopy is conventionally used to study the properties of analytes deposited on an enhancing surfaces, it also works in reverse: Raman spectroscopy of the deposited analytes can be used to study the properties of the enhancing surface. JPL's innovative method of electride-mediated SERS is advantageous for both applications. With the conventional use, the electride enhances SERS spectra as well as conventional enhancing surfaces do. With the reverse, the SERS of analytes provide a sensitive probe of the unusual chemical, optical, magnetic, and electrical properties of the electride surface.
Benefits: 

SERS enhancement factor greater than 104 at 532 nm excitation and greater than 103 at 785 nm excitation

applications: 

Trace chemical analysis

Research on the chemical, optical, magnetic, and electrical properties of electrides - electroactive materials, photonics

Reps: 
Patent Number: 
9,470,634
Internal Laboratory Ref #: 
NPO-TOPS-24
Patent Status: 
Patent Issue Date: 
June 9, 2015
Agency
NASA
Region
Far West
State: 
California
Lab Representatives
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