A simple method to fabricate silver colloid clusters for surface-enhanced Raman scattering

► We have developed a simple method to fabricate silver colloid clusters for SERS. ► Silver colloid particle clusters are fabricated by following a three-step process. ► Immobilizing colloid particles on poly(4-vinyl pyridine) films. ► Adsorbing molecules on the immobilized particles, and then immobilizing colloid particles again. ► The calculated enhancement factor is approximately 1 × 106.