Quantitative Discrimination of Silver and Gold Nanoparticles Immobilized in Transparent Plastic Film by Photothermal Microscopy with Multiwavelength Excitation

Silver nanoparticles (AgNPs) and gold nanoparticles (AuNPs) immobilized in a poly(vinylalcohol) film on a glass substrate were quantitatively discriminated by photothermal (PT) microscopy with multiwavelength excitation. AgNPs and AuNPs showed discernable PT signals at excitation wavelengths of 405 nm and 520 nm, respectively. The mixed ratios of nanoparticles determined by PT signals were in good agreement with those calculated from their concentrations. Silver nanoparticles (AgNPs) and gold nanoparticles (AuNPs) were immobilized in a poly(vinylalcohol) film on a glass substrate and they were quantitatively discriminated by photothermal (PT) microscopy with multiwavelength excitation. The mixed ratios of AgNPs and AuNPs determined by PT signals were in good agreement with those calculated from their concentrations.