Very thin spin-coated silver films via transparent silver ink for surface plasmon resonance sensor applications

We fabricated very thin silver films with thicknesses of 20 nm, 40 nm, and 60 nm on a prism using a spin coating method for surface plasmon resonance (SPR) image sensor module applications. An aqueous silver ionic complex solution was spin-coated and then thermally cured for 10 minutes at 150 degrees C in an oven. The spin-coated solid silver films possessed silver crystallinity. The prism modules with the 20-nm-, 40-nm- and 60-nm-thick thin silver films were applied to an SPR image sensor system. The coefficients of determination for the 20-nm-, 40-nm- and 60-nm-thick silver films were 0.923, 0.990 and 0.989, respectively when standard ethanol solutions with 0.1% intervals in the range of 20.0% to 20.5% were applied. The correlation is high-performed and the coefficients of determination are as close as 1. The spin coating method of very thin silver films for SPR image sensor modules is expected to be a very cost-effective solution because the films can be formed at a low temperature in a short period of time without requiring a vacuum system.