• Keller, Stephan Urs
• Boisen, Anja
• Rindzevicius, Tomas
• Wu, Kaiyu
• Nguyen, Long Quang

Abstract

Polymer-based surface-enhanced Raman spectroscopy (SERS) substrates offer distinctive advantages such as low-cost and high optical transparency which allows direct detection of trace chemicals on target surfaces and easy microfluidic integration. However, incident-laser-induced localized surface plasmon resonances can generate heat that deform the polymer and significantly reduce the intensities of recorded SERS signals. Herein, a novel wafer-scale polymer-based transparent nanocoral (WTNC) SERS substrate with 3D electromagnetic "hotspots" is presented. Its fabrication is simple and lithography-free. The novel SERS substrate demonstrates excellent nanoplasmonic heat resistance, high SERS sensitivity, and unmatched SERS signal uniformity with a relative standard deviation of approximate to 6% across 80 mm. Excellent photothermal stability is achieved by highly crosslinking SU-8, a negative epoxy photoresist, raising its initial degradation temperature to approximate to 230 degrees C, much higher than the glass transition temperature of state-of-the-art thermalplasts used in SERS substrates, including polyethylene terephthalate and poly(methyl methacrylate). The WTNC substrate can withstand very high laser irradiance of up to 300 kW cm(-2), enabling superfast SERS imaging of analytes in extremely small quantities. A high resolution SERS image containing 10 201 spectra of approximate to 44 amol trans-1,2-bis(4-pyridyl)ethylene is obtainable in

Topics

• impedance spectroscopy
• surface
• polymer
• glass
• glass
• glass transition temperature
• Raman spectroscopy
• lithography
• degradation temperature
• heat resistance