Flexible Multicavity SERS Substrate Based on Ag Nanoparticle-Decorated Aluminum Hydrous Oxide Nanoflake Array for Highly Sensitive In Situ Detection

Flexible surface-enhanced Raman scattering (SERS) substrates are very promising to meet the needs for real-time and on-field detection in practical applications. However, high-performance flexible SERS substrates often suffer from complexity and high cost in fabrication, limiting their widespread applications. Herein, we developed a facile method to fabricate a flexible multicavity SERS substrate composed of a silver nanoparticle (AgNP)-decorated aluminum hydrous oxide nanoflake array (NFA) grown on a polydimethylsiloxane (PDMS) membrane. Strong plasmon couplings promoted by multiple nanocavities afford high-density hotspots within such a flexible AgNPs@NFA/PDMS film, boosting high SERS sensitivity with an enhancement factor (EF) of ∼1.54 × 10