All-optical nanoscale pH meter.
We show that an Au nanoshell with a pH-sensitive molecular adsorbate functions as a standalone, all-optical nanoscale pH meter that monitors its local environment through the pH-dependent surface-enhanced Raman scattering (SERS) spectra of the adsorbate molecules. Moreover, we also show how the performance of such a functional nanodevice can be assessed quantitatively. The complex spectral output is reduced to a simple device characteristic by application of a locally linear manifold approximation algorithm. The average accuracy of the nano-"meter" was found to be +/-0.10 pH units across its operating range.
Bishnoi
Sandra W
SW
Department of Electrical and Computer Engineering, Laboratory for Nanophotonics, Rice University, P O Box 1892, Houston, Texas 77251-1892, USA.
Rozell
Christopher J
CJ
Levin
Carly S
CS
Gheith
Muhammed K
MK
Johnson
Bruce R
BR
Johnson
Don H
DH
Halas
Naomi J
NJ
D004867:Equipment Design; D019544:Equipment Failure Analysis; D006863:Hydrogen-Ion Concentration; D036103:Nanotechnology / Q000295:instrumentation* / Q000379:methods; D055095:Optics and Photonics / Q000295:instrumentation*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013059:Spectrum Analysis, Raman / Q000295:instrumentation* / Q000379:methods; D013499:Surface Properties; D014159:Transducers