One-pot preparation of thin nanoporous copper foils with enhanced light absorption and SERS properties

Abstract

ARTICLE This journal isA facile hydrothermal method has been presented to prepare the free-standing nanoporous Cu foils (NPCFs) having thickness of ~ 1.4 µm and area up to ~ 10 cm 2 , which were grown on the inwall of Teflon autoclave by assembling and reducing Cu x O nanoparticle intermediates, and then peeling themselves off in the cooling period of the reaction. The pore sizes of NPCFs can be adjusted by varying the reaction time. It is observed that the NPCFs with water absorbed inside their nanopores show excellent flexibility while a dried one exhibits highly hydrophobic nature. Compared with commercially available Cu foils, the as-synthesized NPCFs show enhanced ability to absorb light over a wide range of wavelengths from 200 to 1000 nm because of their nanoporosity. The highest absorbance and the biggest enhancement can reach 86 % at 300 nm and 43 % at 575 nm, respectively. The smooth side of NPCFs with hemisphere-like surface demonstrates outstanding surface-enhanced Raman scattering performance by employing rhodamine 6G as the probe molecule, which agrees well with the results of finite-difference timedomain simulation.

Porous metallic nanocone arrays for high-density SERS hot spots via solvent-assisted nanoimprint lithography of block copolymer

“…One of the approaches to fabricate the structures with dense hot spots is using porous nano materials such as porous silicon, [11][12][13] anodic aluminum oxide (AAO), 14,15 and nanoporous metal. [16][17][18][19] Internal pores or protrusions on a scale of tens of nanometers excites LSPR and thus can be strong EM hotspots. The pore size is tunable by controlling the fabrication conditions, so that LSPR response can be optimized with respect to the wavelength of the excitation light source.…”

Chemically Etched Nanoporous Copper and Galvanically Displaced Silver Nanoflowers for SERS Sensing

“…The extinction spectrum exhibited quite a resemblance with those reported for copper foil. 43 Therefore, this observation served as the first indication of Zn's leaching from brass, leaving Cu in a nanoporous state (Cu NPS ). While the Ag nano @Cu NPS SERS substrates obtained through galvanic displacement displayed a diminished absorbance at 530 nm accompanied by the emergence of broad bands above and below this wavelength.…”

Hierarchically porous micro/nanostructured copper surfaces with enhanced antireflection and hydrophobicity

“…The XRD patterns (Fig. 1b) suggest that all diffraction peaks for the bare and the micro/nanostructured Cu foils are well matched with face-centered cubic Cu (JCPDS 04-0836, space group, Fm3m) [22]. These peaks at 43.3, 50.4 and 74.1 • correspond to crystal faces of (1 1 1), (2 0 0) and (2 2 0) of crystalline Cu, respectively.…”

“…3b 1 ) were grown on the surface of Cu foil. As reported in our previous work, Cu x O nanoparticles formed on the inwall of the reactor when the reaction time was less than 2 h [22]. So the Cu microparticles were produced by reducing the assembled Cu x O nanoparticles on the Cu foil substrates.…”

“…It was supposed that the growth could be controlled by adjusting the EG amount added into the precursor because EG was found to be a key factor for the formation of Cu seeds on the substrates [22]. Fig.…”