Graphene Grown on Ni Foam: Molecular Sensing, GERS, and Galvanic Exchange for SERS Applications.

MERCEDES, MESSINA; PICONE, LORENA; CECILIA, DOS SANTOS CLARO; REMIGIO, RUIZ; FABIO, SACCONE; ROSANA, ROMANO; FRANCISCO J. IBAÑEZ

JOURNAL OF PHYSICAL CHEMISTRY C

AMER CHEMICAL SOC

Lugar: Washington; Año: 2018 vol. 122 p. 9152 - 9161

1932-7447

The growing of graphene on irregular 3D Ni structure demonstrates to be an interesting platform for, molecular sensing, GERS, and SERS applications after galvanic exchange of Ag+ ions. Raman, SEM (EDS), optical images, and diffuse reflectance exhibit that graphene grows along the entire surface of Ni in a multilayer (MLG) stacking. Raman statistics show that as-grown graphene can be classified in two main stacking configurations: AB-stacking and rotated graphene which are separated by a 2D full-width half maximum (fwhm) threshold of ~30 cm-1. Rotated configuration senses low concentrations of methylene blue (MB) at 10-6 M concentration, whereas AB-stacking seems to be much less sensitive upon molecular adsorption. Galvanic exchange leads to agglomerates preferentially formed on top graphene wrinkles which ultimately became target-spots for performing SERS. Our experiments demonstrate that the limit of detection for both analytes is in the order of 1 x 10-9 M when the laser (red and green) is placed on top of those Ag agglomerates.