Surface roughness boosts the SERS performance of imprinted plasmonic architectures

Abstract

The large-area low-cost rough plasmonic crystal (r-PC) SERS substrates introduced herein outperform smooth counterparts and rough films both in magnitude of the Enhancement Factor (EF) and in the number of vibrational peaks displayed in the Raman spectrum. In r-PCs, photonic modes launched by the lattice excite more intense and abundant localized resonances in the sharp edges and gaps present in the rough metal surface. 2D r-PCs are fabricated by nanoimprinting a nanocrystalline titania paste followed by silver coating, resulting in a highly reproducible rough photonic architecture. The SERS performance of these architectures is tested via detection of two molecules; Benzenethiol and 4-Mercaptopyridine. The resulting EFs exceed 10 7 in the case of Benzenethiol and 10 10 when using 4-Mercaptopyridine. The simple fabrication strategy and the high performance exhibited by these nanoimprinted substrates, place rough plasmonic architectures as one of the most promising candidates for inexpensive and efficient mass-produced SERS substrates.

Indirect Interactions between Raman Probes Encapsulated within Cucurbit[7]urils and Gold Nanorods to Enhance Long-term Stability and Signal

“…Rhodamine 6G (R6G), used as a Raman probe, was obtained from Sigma-Aldrich (St. Louis, MO, USA). Cucurbit [7]uril (CB [7]) was synthesized by following the procedure as described previously. 21…”

“…[2][3][4][5][6] SERS is a technique that powerfully enhances Raman signals by adsorbing target molecules on rough metal surfaces, which are most commonly metal nanoparticles. 5,[7][8][9] However, SERS is also limited because of strong interactions between the Raman probe molecules and the metal surface, which are necessary for the stable enhancement of the signal. To improve the long-term stability of Raman enhancements, previous studies have attempted to develop additional approaches and strategies, such as the introduction of SERS stability in several biological applications.…”

“…Herein, we introduced CB [7] to overcome SERS limitations, such as unspecific adsorption, weak interactions, or low stability with gold surfaces, which all lead to difficulties when using SERS. 20 We sought to produce stable AuNR aggregations using CB [7] to yield regular alignments to understand the role of CB [7] and its interaction with AuNRs. Moreover, we performed a SERS study of R6G with the AuNR aggregates; CB [7] acts as a container to discern the long-term stability of this system.…”

“…20 We sought to produce stable AuNR aggregations using CB [7] to yield regular alignments to understand the role of CB [7] and its interaction with AuNRs. Moreover, we performed a SERS study of R6G with the AuNR aggregates; CB [7] acts as a container to discern the long-term stability of this system. CB [7] allowed us to stably capture R6G in the CB [7] cavity, which we verified with stable SERS signals.…”

“…Moreover, we performed a SERS study of R6G with the AuNR aggregates; CB [7] acts as a container to discern the long-term stability of this system. CB [7] allowed us to stably capture R6G in the CB [7] cavity, which we verified with stable SERS signals.…”