Enhancing the upconversion photoluminescence of hexagonal phase NaYF4:Yb3+, Er3+ nanoparticles by mesoporous gold films

Abstract

Efficient enhancement of photoluminescence in rare-earth activated upconversion materials is of great significance for their practical applications in various fields. In this work{,} three-dimensional mesoporous gold films were fabricated by a low-cost and facile dealloying approach to improve the upconversion photoluminescence efficiency. The mesoporous Au films exhibit good chemical stability{,} large-area uniformity and abundant distribution of porous nanospaces. Varying the time of the dealloying process leads to modification of pore size distribution{,} surface roughness and residual Ag content{,} resulting in effective tuning the wavelength of the broadband localized surface plasmon resonance (LSPR). Enhancement factors were identified to be a function of the dealloying time. With the optimized upconversion photoluminescence enhancement a 41-fold increase was achieved with the mesoporous gold substrate which had been dealloyed for 8 days. These results pave the way to overcome the limitation of poor upconversion efficiency for widespread practical applications in life sciences and energy applications.