A facile route of microwave to fabricate PVA-coating Ag nanofilm used as NIR-SERS active substrate

► The fabrication rout of the PVA-coating Ag nanofilm is facile, low-cost and time-saving. ► The maximum plasmon resonance band of this Ag nanofilm is at ∼780 nm, indicating a good NIR characteristic. ► PVA-coating Ag nanofilm fabricated using this simple method is highly NIR-SERS active (EF ∼ 107). ► The roles of PVA molecules employed in fabricating of PVA-coating Ag nanofilm are studied.