Sacrificial polymer thin-film template with tunability to construct high-density Au nanoparticle arrays and their refractive index sensing

Great challenges still remain to assemble metal nanoparticles on a substrate with tunability, high density, robust stability, good dispersion and well-retained properties for various applications. Herein a new concept using a polymer thin-film as a sacrificial template is investigated to fabricate highly dense and well-dispersed nanoparticle arrays. In contrast to a conventional hard template, the polymer template is a porous multilayered film allowing in situ growth of Au nanoparticles with a restricted ripening mode, and tuning the nanoparticle size and density of the arrays is possible by simply adjusting the loading conditions. The prepared substrate-attached nanoparticle arrays demonstrate good thermal and chemical stability, while offering highly sensitive and tunable localized surface plasmon resonance (LSPR) refractive index sensing with a broad linear dynamic range. This method could be extended to controllably fabricate other robust and clean nanoparticle arrays on various substrates for various applications including sensing, catalysis and optoelectronics.